Small and large packages, thick envelopes, and tubes can be sent using Media Mail. Contents are limited to books, film, manuscripts, sound recordings, video tapes, and computer media (such as CDs, DVDs, and diskettes). Sometimes called "Book Rate," Media Mail cannot contain advertising. Media Mail is less expensive than Parcel Post.  If your packages weighs less than 6 ounces, FIRST-CLASS MAIL is less exspensive than our beloved MEDIA MAIL.