$500 can do lots of things! You could get 2000 25 cent packs of gum. Hire an attorney for 2.5 hours (depending on the going rate of attorneys). You could even book a cross country trip on a Greyhound bus for much less than $500.
If you are talking about computers, then I know Best Buy has some okay laptops for under $500. They are fine for Internet and Kongregate, but not the best for high resource games.
If you have the knowledge and ability, $500 can also be used to buy yourself the parts to buy you a decent computer as well.