What is the best (FREE) way to learn economics as it relates to trading?
You can start from reading some books on economics and trading. Good economics for hard times and The automatic millionaire are worth a try in my experience.
Economics of course directly affects trading activity and not only it. The best way to learn economics as it relates to trading is to buy books which somehow relates to economic of course. You should properly leanr some themes like supply and demand, GDP, various indexes, the appearance of modern economic systems and information about previous economic systems. Basically, I think that there are no some themes in economic which don’t relate to trading, to my mind everything relates to this activity. So, you’d better start from the very beginning of economics, its history, world market and stuff like that. World economic is the best teacher for traders.