I love to understand things... even bureaucratic German parcel prices

Last time I paid EUR 2,20 to ship a book I sold on Amazon.

Today I learned that this was the "Maxibrief" Tarif. And that for the same size and weight, one can use the "Maxibrief Büchersendung" for only EUR 1,40!
http://www.geldsparen.de/content/dienstleistungen/index.php?artikel=buechersendung
And here are the measures:
http://www.postsitter.de/tarife/buchsdg.htm

The only trick is to write BUECHERSENDUNG above the address and to use an "open packaging" which means: it can be opened and closed without damage. Here's how to make that:
http://frederick41.de/buchverp.html

Fortunately, there's the fine German invention of Musterklammer! (Well, probably other countries have that too, but the word is so special, it's not in the dictionary.)

Now, it's even more comfortable to reuse my Amazon packagings and the people buying books from me get a reusable packaging for free. (I only need to buy a box of Musterklammers, hehe.)