If I where you I would try Ebay. I have bought many highend parts that I could of only afforded because they where used. It is a real good alternative for someone on a tight budget.
For Example I picked up a 6800GT that normally costs about $450 new. I picked one of ebay, it was used but in great condition for $270.00, It did not have an installation disk, but I was able to download the drivers online.
I mean think about it!!
For $270.00 I bought one of the top video cards on the market!
You have to remember too, that we are dealing with electronic equipment, Wear and tear of regular use does not really apply to effecting its performance. So to call it used is only saying it was taken out of the package, Thats my opinion.