Not knowing what game you intend to use it for or what lvl raiding or not etc. Im going to guess you know that under 150 or so you will live with the sub par performance of said card.
Normally I wouldnt reccomend anything under a 9800 gt with 1gb but I do understand a tight budget.
So with that discalimer these are the two best performing cards i could find in your price range and where to get them.
http://www.geeks.com/details.asp?invtid=288-10N43-130EV&cat=VCD
thats a 9600gt
http://www.geeks.com/details.asp?invtid=SFPX95GT512U2L&cat=VCD
and the less expensive 9500gt.
Both cards have 512mb of ddr2 ram on board and should give a decent gaming experience.
I would after buying any geforce 9xxx card download evga precision tools as some of the drivers are quirky and this will allow you to turn up the fan rate to
100% while you are playing to avoid any heat problem that could arise. After that get the latest nvidia driver and have fun. Also make sure you have a sufficient power supply to run either of these cards before you buy them. I would say the minimum is 500w for either although I could aslo be off since i personally never used them.