Make sure your CD deck is Mp3 compatible too man.
But yeah breakbeat.co.uk, beatport.com, djdownload.com.
This is good to have but isn't essential, I never use MP3 CDs in mine even tho they are, too many tracks on a CD become complicated imo. I'm pretty sure all the big djs i've seen mix have change the CD all the time, maybe 4-6 tracks each.
Scuba the badman has 1 track per cd!
that must be so fuckin expensive!
oh n i usually have like 10-14 tracks on each cd i don't see why people only put like 5-6 on