Amazon is a great place to buy LOTS of stuff. But I and 2 other people I know have been victimized by a new scam. Cards like Titan-X and 980Ti bought from the "Warehouse Deals" section have been 75% fakes.
As in, you open a box for a 980Ti and find a burned out GTX780 with a 980Ti fan installed on it. Several of them have the stickers moved over as well. The quick way to tell is frequently the number of ports. The better new Maxwell cards have 5 or 6 ports on them, while older Kepler cards will only have 3 or 4 ports.
Of course Amazon makes it easy to return the bogus cards, but that doesn't fix everything. Twice I have had to tell someone AFTER they have driver here that the card they got was junk.
And to be clear, this only applies to the USED ones from "Warehouse Deals", the new ones and used ones from specific sellers are probably just fine.