Here's how I send a CD for less than a dollar.

Blank CD-R -------------- $0.18 
Black sleeve ------------ $0.05
Paper for the insert ---- $0.02
Paper for envelope ------ $0.01 (I make my own envelope from copy paper)
Printer ink ------------- $0.03
Postage ----------------- $0.50
--------------------------------
Total ------------------- $0.79

This is called an ecopack. It's the jewel cases that are fragile not the CDs. I almost never get a CD broken in the mail.