You can sell a play station game by placing an advertisement on an internet website dealing in the sale of used product. In addition, one can sell their play station games at any electronics shops that deal with games and other electronic materials.
2 Additional Answers
You can sell your PS2 online at an auction site (like eBay) or you could visit a local computer store that has a trade in program. I know GameStop has one where you get a store credit for used games/consoles.
You can sell your PS2 (PlayStation 2) online at eBay. You can also trade it in for a store credit at GameStop. Check with other local gaming stores, they might have a similar program.