I haven't taken any paid online courses that fit within your budget, but there are plenty of high quality free courses. Depending on your experience, I'd recommend the following:
Highly unpopular opinion, I know, but I didn't find learning how to learn very useful. It might as well have been a 30-minute video, and it wouldn't lose much of its content. A lot of the content seems to be rather inspirational than educational.
Kind of like any book or course like that, I found that the magic wasn't in watching the lectures or reading the book but in deliberately applying some of the strategies to my own learning process.
It was easy to watch and think "OK that makes sense". It was much harder but much more worthwhile to deliberately set aside time for diffuse mode, practice spaced repetition, and quiz myself as I worked through a reading.
I took one class (computer architecture & assembly language) through Oregon State University's online CS program as a soft-requirement for some in-person classes I'm currently taking. They have the full post-bacc program (http://eecs.oregonstate.edu/academic/online-cs-postbacc), and they also do allow you to take one-off classes. Officially it says you can only take the intro classes, but I just signed up for this class anyways.
It was quite a bit more than OP's budget (total cost came to $1,200 or so), but that ended up being much cheaper than having to take the class at my current program. My employer also helped with 2/3 of the cost.
As vikram360 pointed out, they're on the schedule page (https://pdos.csail.mit.edu/6.824/schedule.html). Since this is the class going on right now (Spring 2020), only a couple that have already happened have been posted so far, but I'd bet they're uploaded pretty soon after their date.