Free is a good price.
Everybody loves free stuff, right? Get your free ebooks!
You’ll have to register, of course, and you’ll have to have an ereader of some sort that can display PDF, EPUB, and/or Mobi for Kindle formats (yes, your PC is an ereader).
I’m just sharing in case you have insomnia, too. Heh.
Lots of good MS Press stuff in there!