if the card is in good shape, but i always check for how much i can sell my card and get the new *new card is always better than old one* you should make some research and see if you can get it for less by selling your old then it'd be a better deal than with your friend
So, ct and shrkbay you guys would take this deal in a heartbeat?
well just because you can upgrade does not mean you should. if you are pleased with the ati 4870 (still a solid gaming card) and could use the $60 elsewhere...dinner out, beer, cpu upgrade, car payment, etc., then there is no need to make the deal.
Id say give him 40 bucks it would make it a more fair deal, otherwise I dunno, you could sell you 4870 for maybe 80 or less on ebay, either way its not a bad deal but you will have to weigh the options