I recently wanted to buy some MP3 files from Amazon (a whole album in my case, but you can also just buy single MP3 files if you want). Digital music downloads from Amazon are often much cheaper than buying the physical CD (from Amazon), and you can also instantly get the stuff within seconds, without having to wait for the physical CD to be shipped to your place.
The good thing about Amazon's MP3 downloads is that the files are not infested with any DRM-crap (if that were the case I wouldn't spend a single penny on such useless junk, of course). This allows you to burn the MP3 files on CDs and/or play them on any device you like (MP3 player of choice, laptop, hifi-system, car, e-book reader with MP3 playback support, etc. etc).
Granted, you can not re-sell the digital files on eBay later, this is the one little drawback you have when compared to physical CDs, but I guess most people can usually live with that. Also, it would be great if Amazon would provide Ogg Vorbis files instead (or in addition to) MP3 files, of course.
Anyway, in order to download the MP3 files you buy from Amazon, they suggest to install the Amazon MP3 Downloader, which (surprisingly) is even available in a Mac and Linux version (only 32-bit though), but is (unsurprisingly) closed-source. This is no-go, of course, but luckily there is an alternative.
The clamz tool (GPL, version 3 or later) allows you to easily download single Amazon MP3 files, or whole albums. First, you need to login to your Amazon account and then visit a certain Amazon page (which sets a special "congratulations, the Amazon MP3 Downloader has been successfully installed" cookie in your browser). See the clamz website for the respective URL for your country. For Germany, use this URL.
The clamz installation is easy enough on Debian:
$ apt-get install clamz
IMPORTANT: It seems you need at least version 0.5 for recent Amazon files as they apparently changed something, see #647043. Current Debian unstable as of today already has 0.5, though.
After that is done, the rest is easy: In Amazon, click on "Buy MP3" or "Buy MP3 album", which will download a special AmazonMP3-1234567890.amz file. You can then let clamz download all the MP3s by typing:
$ clamz AmazonMP3-1234567890.amz
Wait a few minutes, and you'll have a bunch of non-DRM MP3 files in your current directory. Easy.
See the manpage for a bunch of options which let you configure clamz to your preferences.