the cheapest you can get that has T&L is the good ol nVidia GeForce Ti4200. its about 2 years old iirc, but my friend i still running modern games with it. that should go for 50-100$ now. if you want the best compromise between price and performance id suggest an ATI RADEON 9700 (go for pro if you want). that goes for 150$ now on
pricewatch. if you want more power, then try getting an ATI RADEON 9800 (pro if needed). id actually recommend this one over the other 2, because it costs just a wee bit more but your gonna get a huge performance increase (especially if you opt for PRO with 256 mb of RAM, thats 220$ on pricewatch).