Buying a used SSD?

i'm giving my macbook pro (specs in sig) to my mom, and I want to get rid of both the 120GB Vertex 2 SSD and the 500GB HDD and just replace them both with a single 256(ish)GB SSD. I don't need a brand new drive, however...the mobo is SATA II, so I think I'd be better off getting her a cheap used drive. Is there anything I should know about buying a used SSD? Things to watch out for? I know a while ago, longevity was a hot topic regarding SSD's...I don't want to buy something that will crap out on me within a year...

Have them run the SMART info or if its a OCZ drive, run the diagnostic on it and check out drive life. That said, its still all a crapshoot honestly unless some SMART data is bad.