I teach chemistry at a community college and we’ve been using OpenStax for a few years now with pretty successful results. The math, physics, and bio departments have used them as well, and I think they are pretty satisfied.

In general, these are great resources for autodidacts, but an even better option is to take a class at your local community college if at all possible. It’s great that the sum of human knowledge is available at the tip of your fingers, but there’s a lot to be said for the scaffolding and structure that higher education provides, because the instructors and the courses really help to make connections that are difficult to understand when you’re learning it on your own.

As an aside, I get that this is a community for autodidacts, but at the college level, it’s really hard to get really good at something on your own. The most gifted and dedicated autodidact I’ve ever known came into my chem classes thinking that it was just a hoop to jump through and ended up thanking me for dissuading him of that idea. And as a bit of not-so-humble brag, he’s now at one of the top 20 universities in the US doing chemistry and neuroscience research. I can’t claim credit for his accomplishments, but I can say that he wouldn’t have gotten there without actually taking that first step and enrolling in a class after already trying to learn it on his own.