When buying games there are a few pointers when making the purchase.
1) Always ask if there is a SERIAL CODE that is unused and original, many sellers use cd-keys that are computer generated, and sell the authentic ones again online.
2) Confirm that all the disks are included, some sellers show a whole heap of items, but you are realy only paying for one thing.
3) If the picture of the disk is not shown, try to stay away.
i have bought cd's that ended up to be copied =|
ask for a picture if possible.
4) As usualy, stay with seller's with a clean record ;) works for me.