FREEDRYERLINT.INFO
By now you've seen plenty of ads for free ipods, xboxes, etc. This one trumps them all, especially in the honesty department. It's free dryer lint! Go ahead and click on the link. You could get something for free! Really. Or not.

Advanced Bash-Scripting Guide
I have to write bash scripts from time to time. It's not quite often enough for me to remember how to do it. :-) This is by far the best scripting guide that I have seen. And it's free, too! The link above is to download the HTML version. There's also a PDF version available. 585 pages of stuff that's actually useful!