Maybe a Used GTX 650?.. or brand new GT 640... the GT640 will perform more or less the same.. a bit better in some things but nothing great.. will be pretty the same, if you can find any good used GTX 650 will be the best for 80~90$
Check Craigslist in your area. I've seen tons of good deals on there. Bought a GTX 680 for a friend for $125. Those deals are very rare but it's your best bet to get something locally for cheap.