I want to learn economics

If you want to understand the behavior of others, including adherence to and deviation from rational axioms, you need game theory. Here is Yale's open course in game theory and it's a good place to start, but it might be difficult if you don't begin with more basic econ.

For more basic things, start with price theory (aka microeconomics). Ignore macro for a while--money and banking is essential, especially if you want to see through silly discussions about monetary policy, but macro models are less important, in my opinion. Here are some texts on the micro front. Alchien and Allen are particularly readable, but somewhat dated. Note that there are basically no high school level economics texts listed there; I am not familiar with a single good high school text either.

You should ignore most popular books like Freakonomics. They are good, but in my experience don't give readers enough of a general idea of the underlying concepts. An exception is Landsburg's The Armchair Economist, which has popularized explanations of utility, opportunity cost, indifference, and efficiency, all of which seem very difficult for the public to grasp.

Likewise don't read "the classics," unless you're specifically studying history of economic thought. Smith, Ricardo, and so on are too much of a chore for material that is thoroughly dated. We know much more now and we know how to say it better.

Some essays are often much better textbook discussions. Here is an example; I would assign that essay for an intro micro class any day.

Edit: I should say "select chapters" of Landsburg's book are good. Some quite miss the point of the arguments he's trying to rebut. It might be hard for a beginner to tell which chapters are which.

I'm flipping through my Alchien and Allen book again and still seems perfectly relevant and mostly accurate. They've got all the theory down pat and explain it fantastically, it's just that it's missing a few more decades of empirical evidence, so every time they say, "X is what we find in the real world," you have to take it with a grain of salt.

Edit again: Durr. I should note I'm looking at the second edition, 1977.

A bit of recommended reading:

Ricardo's Difficult Idea by Paul Krugman

Have you tried Introduction to Economic Analysis by Preston McAfee?

Do you want to learn the maths, or to gain good intuitions about economics?

Microeconomics

Beginner: Hidden Order: The Economics of Everyday Life by David Friedman.

Intermediate: Intermediate Microeconomics: A Modern Approach by Hal Varian.

Advanced: Microeconomic Analysis by Hal Varian.

Macroeconomics

I would avoid macroeconomics until you grok microeconomics (and maybe even then), but if you must read something, read Macroeconomic Patterns and Stories by Edward Leamer.

More suggestions in an old open thread.

I learned from Mankiw's Principles of Economics textbook. The third edition is cheap on Amazon. I learned a lot from it.

I'm learning and learning to learn economics too. If they're not a primary source for learning, I still find textbooks useful as references. A detailed table of contents and explanations of each concept can be useful when concepts or explanations are omitted from another source. And, if you don't mind reading textbooks cover-to-cover, they tend to be complete.

Here are some free online economics texts. Other commenters are suggesting micro before macro, so go with that. They should all be useful for optimizing the world in specific ways. Reading the introductions of more advanced texts should tell you about how the field is divided and may guide you to realize what you want to study in particular.

Generally, reading criticisms of other theories will save you a lot of time. It protects you from wasting your time reading those other theories. This site is run the the people who organized the occupy wallstreet protests. There's plenty of criticism. I hear they are coming out with a textbook soon.

http://kickitover.org/

If you want to learn some clever and useful ways of economic thinking, I highly recommend "Freakonomics" and "Superfreakonomics," google them for details. They are fun and they figure a lot of unusual stuff out thinking like econmists.

If you want something more orderly, start at the Wikipedia article on economics and keep thrasing around with links from that, including the reference list.

Among the most important principles that may not leap out at you from starting at Economics, I would look at http://en.wikipedia.org/wiki/Comparative_advantage

For the parts of microeconomics and game theory which abut on the decision theory discussed here, I would suggest some of these free online textbooks. Registration required, but is apparently fairly painless - even spam-free.

ETA: One branch of microeconomics that I think is particularly important is "information economics". In the course of Googling to find resources on this topic, I ran into this useful encyclopedia.

Learn this, and most other things at http://www.khanacademy.org/

Here's what I did, which is all I know how to recommend:

0) Absorb liberalism by osmosis.

1) Learn neoclassical economics - price curves, opportunity cost, many of the basic arguments of politicized economics.

2) Learn how especially the politicized stuff is incomplete (should see it coming if you read LW) - evidence for and basics of Keynesian economics, read economic analyses of past trends (growth of trusts, great depression, WW2, silicon valley, banking crisis), economics of public and common goods.

3) Study the world a bit, try and find out what other countries are doing well and how we can copy them. My one book recommendation: Deep Economy by Bill McKibben - excellent book, even if you partly disagree you will be very glad you read it.

Starting with behavioral economics could be a good place, since the applications to daily life are obvious.

some possible books include:

Predictably irrational by Dan Ariely Why Smart people make Big Money Mistakes - Gary Belsky Nudge - Richard Thaler

Read Human action from Ludwig von Mises. PDF: http://mises.org/books/humanaction.pdf Edit: http://mises.org has additional material like a study guide too.