While I did take courses in probability, linear algebra, and lots of calculus, until recently, I forgot most of the probability and all of the linear algebra I learned in school. As for calculus, I only remembered how to take basic derivatives. In any case, I've been spending the past month brushing up on my linear algebra and probability, and it's been a struggle, but now that I'm motivated and under no time pressure to relearn the material, I find it way more fascinating than I did in college. In fact, I skipped tons of my linear algebra classes because I thought the subject was dry and dull. I also rushed through my probability and stats homework just so I could get a good grade on them. I think if you're motivated, and you can do basic math, you should be able to educate yourself in calculus, probability, and linear algebra. It'll be a struggle, but with motivation, you'll be able to pick up the concepts.

for probability and stats: https://www.amazon.com/Introduction-Probability-2nd-Dimitri-...

for linear algebra: https://www.amazon.com/Coding-Matrix-Algebra-Applications-Co...

this was my college calculus textbook: https://www.amazon.com/Calculus-7th-James-Stewart/dp/0538497.... I can't comment if it was good or not because by college, I had taken calculus twice so it was all a refresher

best of luck! You sound educated enough (yes, I'm judging from the couple sentences you wrote) that I think you won't have any problems acquiring math knowledge with persistence.

Realistically, it's money they'll use to buy the Stewart's Calculus ($200) [1] (which, let's be clear, is covering 350 year old subject matter). And then they'll use their financial aid to buy beer.

All of these intro texts (at $150-$200) are broken. They do not go into the subject matter deep enough to use as reference later in coursework or a career and their too expensive to disseminate knowledge widely. Realistically at $30 it's still too expensive to compete with free. But until annotation and referencing UX catches up for e-books dead-tree books still win for learning (I know people manage with PDFs and annotation, but I haven't had success with e-books for anything except for recreational reading). And I think there is a hurdle that is difficult to get over with getting other universities to adopt a university press book from a different university especially for an introductory text.

[1] http://www.amazon.com/Calculus-James-Stewart/dp/0538497815/