If you wait for a Sale at Mushkin.Com, then it isn't so expansive. They have sales quite often, usually 1 or 2 good ones on their DDR memory a week. Plus they usually offer free shipping for short periods two or three times a week. You just gotta keep checking the site.
Just a few days ago, they were offering their Duel-Pack 1GB (2x512MB) PC3200 Black Level 2 (the best DDR400 money can buy) for about $305 (not sure exact price). Factoring in their 10% coupon discount brought the price to less then $275, or about $135 per stick of 512MB. With free shipping, this made it cheaper then Corsair DDR400 C2 (the crappy stuff), and almost put it on the same market as GeIL's 1GB-Kit DDR400 Golden Dragon ($220/$110 per stick).
The best thing about Mushkin is that when you buy, you know what your getting. As opposed to other dealers, including Corsair, Buffalo, and OCZ, where the chip varies by batch, and isn't told.