Take a look at the mega thread, I’ve followed it to “awesomePiracy” and found this list: https://shakil-shahadat.github.io/awesome-piracy/#courses-and-tutorials

If it’s something popular you may find your course in public torrent sites.

My tip: if you didn’t find it anywhere, sometimes VPN to India will drop the price in 50-90% of the “original” price.