I really love allofmp3.com. It’s really everything a music download service should be: the site is nicely designed, works perfectly, and allows you to download music in whatever codec you prefer. Since you’re charged by the megabyte, you depending on how much fidelity you’d like. An mp3 album at a reasonable bitrate is only about $2 (beat that, Apple!), but if you want a lossless codec you’ll probably pay about $8 - $10.
Unfortunately, the site’s not yet on the RSS bandwagon — but I fixed that. I’ve got a simple script that ties together BeautifulSoup and the feed generator from Django to produce a new music feed. If you’re interested, you can subscribe to the feed (updated once a day), or check out the code.