A traditional publisher will probably give you an advance, which may not be more than several hundred dollars or so. What many authors don't realize is that the advance is a loan, so any future royalties will be diverted to pay back the advance before you ever receive a royalty check. Since only about ten percent of all books ever sell out their advance, the advance check may very well be the total amount of money you can ever expect to see from that book. So if they're offering you five hundred dollars, ask yourself if you think you could sell enough copies in the next five years to earn more than five hundred. Be honest with yourself, because you're the only one who'll get burned if you're wrong!
If the answer is yes, you'd be better off self-publishing.
If the answer is no, you might be better off having the publisher's marketing department behind you- and getting the money up front in the form of an advance check.