The Debian GNU/Linux FAQ
Chapter 13 - Redistributing Debian GNU/Linux in a commercial product

13.1 Can I make and sell Debian CDs?

Go ahead. You do not need permission to distribute anything we have released, so that you can master your CD as soon as the beta-test ends. You do not have to pay us anything. Of course, all CD manufacturers must honor the licenses of the programs in Debian. For example, many of the programs are licensed under the GPL, which requires you to distribute their source code.

Also, we will publish a list of CD manufacturers who donate money, software, and time to the Debian project, and we will encourage users to buy from manufacturers who donate, so it is good advertising to make donations.