Leo Babauta has written a book titled The Power of Less and has also released a free companion ebook titled Thriving on Less. You can read about the ebook here and download the free version here.

I did a quick read of the 27-page ebook and it's chock full of common sense hints on simplifying your life and living frugally.  As you'd expect it's a teaser for the print book which the author recommends that you buy, but the ebook is of value in and of itself and is a good quick read for tips on simplifying your life.

Babauta also writes a blog at ZenHabits that you will probably enjoy if you like the book.  In these times I think we can all benefit from a little more simple living.