I just finished reading Economics in One Lesson by Henry Hazlitt, and I am very glad that I did. I would highly recommend this book to anyone interested in learning a pretty basic, but still very thorough, understanding of free market/Austrian economics. An online version of the book can be found here. If you are looking to buy the book its for sale at the Mises Institute here.
The art of economics consists in looking not merely at the immediate but at the longer effects of any act or policy; it consists in tracing the consequences of that policy not merely for one group but for all groups. -Henry Hazlitt