Unless you liked it slim, I'll suggest you to get the Jasper as there're no longer a reliability issues on the current xbox360.

Check if the Microsoft seal sticker by remove the faceplate on the console if you want an original console.

Rule no 1: Always skeptical to ANY used console seller. Tey might cheat you and selling sky high price.
Rule no 2: Don't buy a console from other region. You'll regret for other games.
Rule no 3: If you really think you want FFXIII, get a PS3. It looks much better than the XBOX360 sub-HD version.
Rule no 4: If your only reason for rule no 3 is to go to Playbox copy, keep it to yourself and don't announce it here or this topic will be closed very soon.