Udemy offers the Investing In Stocks: The Complete Course for $10. (You may need to apply coupon code "PCWORLDOCT2017" to see this price.) That's $190 off list and tied with last week's mention as the lowest price we could find. This course teaches you the basics of investing in the stock market with stocks, mutual funds, and ETFs. It includes lifetime access to 10 hours of on-demand video.