depends on what you're gonna do with it......
I picked up an OEM version of the Yamaha YMF-724 (DX-XG Chipset) PCI Card for $20. It's not the greatest card for gaming, but sonically is pretty damm clean, (as far as low end cards go).
I use Logic Audio (don't know if anyone's familiar with it), and it's one of the VERY FEW recomended and tested 2-track Cards (due to low latentcy times). I do as many as 24 tracks (playback) simultaneoulsy, and it handles quite well considering that there isn't much DSP built into the card. I have it in my 'Classic' Athalon/KA7 setup. The only drawback to it is the 1/8" stereo input jack is pretty flimsy, i've had to re-solder it a few times.
but best of all - it's 2K Compatible.
EDIT- Billabong's link will take you to the Re-Bagged version of my card, w/surround, and SPDIF.