R7 260X, that's probably the best budget (less than USD100) graphic card you can buy right now which have good support for both FOSS and proprietary driver for GNU/Linux. I'm still contemplating about getting this card.
Two reasons. The hefty price, average local price is around MYR470+ and unsure support in Debian Wheezy with backports kernel (>= 3.13). If possible, I would like to stick with Debian Wheezy and FOSS driver. It would be even better if I can get WebGL to work in Chrome.