Does Gamestop in Canton GA have Sonic Adventure?

Try going to their website, if they have one, and see if there's a list for games that are available. Alternately try asking for their phone number next time you visit the shop, and you can ask them if they have a certain game at any time. You could also ask them to call you or send you a text message if they happen to get a game that you are looking for.

You could also just go ask for that game.