The United States Postal Service offers many services, and one of them is Media Mail. People may confuse this with the USPS's "Book Rate", but Book Rate and Media Mail are actually the same thing. The name of the Book Rate was upgraded to include all formats of media, and thus, Media Mail was created.
The Book Rate and Media Mail are both provided to consumers and business owners as inexpensive ways to send a variety of media items. When you go to a Post Office, you can refer to either name, and the postal worker will understand which type of mail you are asking for.
The USPS has specific guidelines for sending items under Media Mail. The lists of allowed items are video tapes, film, sound recordings, books, manuscripts, CDs, DVDs and floppy or Zip discs. Magazines are not included on this list because magazines contain advertisements, and advertisements are not allowed to be sent through Media Mail.
The Book Rate was mainly for books when it was first created, but if your intention is to send books to or from a library, then you should use the cheaper alternative known as Library Rate. This is a lot cheaper than Media Mail and provided exclusively for libraries.
Media Mail prices are assorted by weight with the minimum price set at $2.23, as of late 2008. The maximum amount of weight a package can weigh is 70 lbs, and a 70-lb package will cost $26.38. The rate of increase is $.35 a pound. The box can only measure at 108 inches combined width and length.
USPS says that the packages are typically sent and received within 7 to 9 days, but this can vary by location. The further away you send your package, the longer the package will take, but if you send it within the same state, expect the package to arrive within a couple of days.