As of 2015, Media Mail rates start at $2.72 (1 lb.). Use Media Mail when sending books, videotapes, DVDs, CDs, printed music and other sound recordings and you'll save close to 50% off on postage shipping costs.
You can buy postage stamps and send Media Mail with Stamps.com
As of May 31, 2015, USPS Tracking is FREE for Media Mail packages!