Textbooks compile information about a subject into one cohesive whole for study. They're super useful, even though they are too expensive typically. Library Genesis is great for obtaining textbooks you can't afford to purchase.

Textbooks are pretty nice to learn things on your own or as a supplement to classes. If you can find free ones online or at a library, definitely worth it. Full price, not so much.

Edit: I know this post is about economics textbooks though, so I can't speak on those. However, I do think textbooks in general are a great resource that tends to get underappreciated.

You think economics picture books would be a better idea?