Sam,
I don't remember off hand what I priced my CD at for CDBaby, but they sell it for just under $13 at thier site, and Amazon sells it for about $13.50. Each retailer can decide how much to sell for. What you're doing is deciding how much you want to make off each one. You can also set a different price for wholesellers. People like to be able to (and expect to) buy things a little cheaper online, but I wouldn't go too cheap or they'll think what you have must not be very good if you have to almost give it away.
As to Disc Makers, I imagine yoou could just send them something as a typical image file as long as you follow their size and quality guidelines, like a 150-dpi bmp etc.