For superheroes who don't have any moral qualms about it and who can handle the increased responsibilities and exposure, it's a good deal.  Most heroes have moral qualms, want to remain focused on their superheroics and personal lives, and need not risk any additional prying into their identities as a matter of exposure... so it's incompatible with a lot of heroes.  For most corporations, however, it's not a good deal.
 
A corporation sponsoring a superhero publicly in a world of crazy supervillains opens itself up to reprisal from said villains who only need the slimmest of pretense to begin attacking your employees, infrastructure, etc. in order to get at the hero who typically hides behind a secret identity.
 
A corporation sponsoring a superhero would represent deep pockets to be sued whenever the superhero does anything with liability attached (in The Incredibles, the heroes were essentially government sponsored so when the lawsuits started pouring it wasn't the heroes that went bankrupt, it was the government who covered the losses and then regulated superheroes out of existence because they couldn't afford the liability).  This gets particularly messy if the superhero starts acting in the corporations interests against rival corporations like Iron Man inevitably has to. 
 
Of course, it depends on the degree and success of the sponsorship.  If the hero is reaping such great profits (and behaves themselves to limit liability) such that insurance is good, security is paid for, and lawsuits can be handled, then a corporation might consider the risk worthy.  Alternatively, if the sponsorship is diffuse and minimal (rather than a single sponsor with control over a hero, merely one of many sponsors for the same hero, or rather trivial sponsorship like a toothpaste ad) then the risks are lower too.  Of course, that might not matter to a crazy supervillain either way. 
 
These risks tend to be greatly mitigated if superhero corporations sponsor other superheroes.  Iron Man is already subject to all the problems of corporate sponsorship so how does signing up Spider-Man really hurt?  Given the prevalence of mega-wealthy superheroes and their community spirit, I'm surprised there aren't more self-governed internal stipend / support systems in place. 
 
Thanksgiving is around the corner and no doubt we'll see pictures of costumed heroes sitting around a giant turkey as family... what's more family-like than borrowing money? :P

Potential problem is what price would any such sponsor require from a hero that they were supporting financially. Public appearances perhaps? And just as a hero may not turn up to save the world because he is figuring out how to pay the rent, what about the day when a hero doesn't turn up because he is fulfilling his contractual obligations to his corporate sponsor?

Really, do unstable molecules just grow on trees? You'd think his clothes would be even more expensive. Not to mention tailor made to each person's requirements.

There is also the issue of what products you use. There are some people who get in trouble with sponsors for using a rival product. Such as a headline spokesperson for Pepsi being photographied drinking a Coke. They are basically dictating what you can or can't use, and you are obligated to by contract.
 
Sometimes I wonder about a celebrity getting bad press hurting the product. Just look at Charlie Sheen and his latest actions. Has that hurt his TV show at all? If anything, ratings will probably go up.

I think this was an issue handled in that TV series Lois and Clark: The New Adventures of Superman. Some guy was using Superman's likeness to sell merchandise. Eventually they came to a sort of deal. This guy could continue to sell these items, but much the the money had to go to charity.

I know nothing that got Corporate Sponsors that hasn't turn to be the worst possible thing. 

More tied to the "get paid" line of thinking... Spider-Man's money situation just should not exist. 
 
In the real world we provide fellowship and grants to allow people with special skills (medicine, law, academia, etc) to use those talents for society's good even if not profitable.  That's exactly the superhero's dilemma.  They have special skills- powers- and want to use them for society's good- heroism- but it's not profitable.  One could argue that Peter would be too proud to ask for money, but that's why fellowships and grants work... they overcome the stigma of a handout because they're given in recognition of the special talent and of the selfless good... they let the recipient do what's best for everyone rather than struggle with money troubles.  Peter has chased down academic scholarships before, so he's clearly not above this type of merit/need based grants. 
 
If the Marvel US government can put together an entire Initiative to sponsor and train heroes, I'm stunned that between the fortunes of Stark, Rand, Strange, Worthington, Xavier, and so on there isn't a prestigious Superhero Fellowship or Grant system.  What is pocket change to them would easily transform the lives of many Marvel heroes.  I mean Stark, Reed, Xavier, etc. can conspire to control the fate of the planet... they'll reshape reality for Peter Parker... but they won't spend the ten seconds to have someone draw up a Trust or Foundation to make sure worthy superheroes aren't having their lives and heroism compromised by money problems? 
 
People might argue as a matter of theme readers can't identify with that, but again, scholarships, grants, and fellowships are in the real world!  If you've never chased or got one, I'm sure that someone you know or someone they know has. 
 
EDIT: And, now that I think about it, Xavier does seem to do this for all his X-Men... I mean, how many of them have identifiable day jobs?  How many of them have money troubles like Peter?

If the Flash was sponsored then nobody would see the company logo/ the ads. :D

hahaha I love the Superman one!
 
For 5000 dollars in advance!

Reminds me of this guy in the Mystery Men movie 
http://www.adherents.com/lit/comics/image_film/MysteryMen_03.jpg

I don't think so. Because Superheroes who are (well heroes) don't need to ask for money. Besides working like the heroes for hire team is like having a secret identity, but working a job like the Daily Bugle, and also receiving money for being a hero.

Who cares? Booster Gold still put his ass on the line and saved the city, the universe, the multiverse, and time itself hundred of times. If you have a way to make money legally than God Bless, Also Booster uses high tech equipment he needs money to fund that 

Absolutely not. Superheroes are role models, examples and certain heroes such as Superman, Batman and Spider-Man have an impact on our culture as well. To have them become a part of a corporation despite the fact I know some do (looking at you Booster Gold!) demeans them and their raison d'etre for becoming a hero in the first place to protect the innocent regardless of fame or fortune. They're like law enforcement officers only super powered so they shouldn't become a superhero for the money. Besides, that's what secret identities are for and several heroes get by without being a billionaire play boy or have access to advanced technology.

The problem with corporate sponsors for heroes is that it could create a conflict of interest. If Booseter is sponsored by Nike, what happens when he needs to shut down a Nike sweatshop using child labor? The sponsor might pull out, thus he is  disincentivized to stop crimes committed by his sponsors.

Isn't Batman corporately sponsored?

" I don't think so. Because Superheroes who are (well heroes) don't need to ask for money. Besides working like the heroes for hire team is like having a secret identity, but working a job like the Daily Bugle, and also receiving money for being a hero. "

"Absolutely not. Superheroes are role models, examples and certain heroes such as Superman, Batman and Spider-Man have an impact on our culture as well. To have them become a part of a corporation despite the fact I know some do (looking at you Booster Gold!) demeans them and their raison d'etre for becoming a hero in the first place to protect the innocent regardless of fame or fortune. They're like law enforcement officers only super powered so they shouldn't become a superhero for the money. Besides, that's what secret identities are for and several heroes get by without being a billionaire play boy or have access to advanced technology."

Cyclops and the X-Men need a sponsor

absolutely not. let's not even discuss the fact that it would go against everything that a hero is supposed to stand for. what happens when the company or sister company of your sponsor commits the crime? what happens when the CEO of your sponsor starts lobbying and has influence over the hero community through you, to further their own business interests?  
 
this would be a huge conflict of interest waiting to happen

@satanmode:
Hahahahaha, ya beat me too it~ Totally my second fav sell out. ^_^ 
 
 
 
Also, seriously, if you are a hero, it's gotta be hard to hold down a real job an be able pay for your living expenses, a lil extra cash from sponsership could really keep the side things in check.

We can't all be paid by Bruce Wayne, Tony Stark, or Oliver Queen.

haha..He said booster gold..

if popular enough heroes could get toy sponsorships to make toys of themselves
 
There probably kids in Metropolis with superman action figures

Actually, Reed Richards supports his family primarily by selling off patents for his inventions...in fact the FF have gone broke once or twice when that well dried up. I'm sure he sees money from all of the unstable molecule costumes in the MU...the X-Men alone must represent a small fortune.
 
Of course this isn't the same as being corporately sponsored and really the FF are really a team of science explorers who fight aliens way more than costumed villians. Though Ben or Johnny may fight crime individually, the team as a whole doesn't do street level crime.
 
Even though he quickly gave up being a celebrity, Peter Parker makes a living of his alter-ego by selling pics of himself in action to the Daily Bugle. And Luke Cage was the Hero For Hire, though he always seemed to not get paid for his heroics in the end.

Probably only mostly the all american boy scout types. 

Wasn't this already covered during Kingdom Come? 
Superheroes don't need endorsements, just like corporations don't need private armies.

Actually I strongly believe they should.  Hero's still have lives, and have to pay bills, but if the public wants a hero to be a hero 24hrs a day then they need to pay him somehow.  Not all hero's are Bruce Wayne or Tony Stark.  I always thought that Superman, most likely the most important hero any where should be a 24 hr hero.   He could Easily take something like a satellite and throw it where ever NASA wanted it.  By doing this, Superman saves NASA millions, maybe billions in rocket fuel, and engineering of ships that lose certain parts once they break orbit.  Superman could charge a quarter of what NASA usually loses and make millions.  Also he would only work for a few  hours.

I really think it all depends on the type of characters~
 
GOLD, like BOOSTER GOLD!!
 
But being "sponsored" and not "promoting" can be two separate things. Like some voluntary firemen are. (to buy their equipment and stuff)

These guys were all in the heroics for money or fame: 
Dollar Bill 
Luke Cage 
X-Statix 
Heroes for Hire 
Youngblood 
Wildguard 
Hero Hotline 
Should I go on?

hey in the fantastic four movie (rise of the silver surfer)
johnny introduce susan a costume full of adverts didnt he???