Really depends on what you want to know. If you are totally new to the concept of money system, YouTube videos like this one [1] (it has three parts) have the best return on your time. Politically loaded but gets basics right.

If you want very condensed crash course in investing, economics, corporate finance etc., I can recommend CFA exam preparation materials. You do not need to take exam to get them, there are plenty of used books available for sale, and you can get them on the cheap as you are not worried about them being up-to-date

[1] https://www.youtube.com/watch?v=I_x626joik0 https://www.youtube.com/watch?v=l_IgcmsqnVM https://www.youtube.com/watch?v=rxZhtGeRa-M