I'm trying out allofmp3.com - a mp3 sales site based in Russia. heh heh. Sounds way too shady to be good but there were a bunch of people on Slashdot who've been using it for awhile and haven't had any problem. I paid $10US through Paypal (so about $15Cdn) which gives me 1GB of downloads at whatever encoding rate I choose - including AAC (mp4 - what Apple uses). A 5 minute song encoded at 192k AAC is roughly 5MB. 1000MB (1 GB) divided by 5 is 200. 200 songs for $15 is pretty good. :) It's about $0.08 per song. Because I paid through Paypal they don't have my credit card number so at worst I'd be out $15.
Basically you choose the songs you want, the rate you'd like them encoded at and then they send you an email when it's ready to be downloaded. I'll let you know how it turns out.