Assuming you are looking for primarily video content:
- Go deep into some recent-ish tech stack, e.g. React/Flux: Udemy
- Learn foundational stuff, like math: Coursera
- iOS: Bitfountain if you can afford it. Otherwise Udacity or Udemy.
- Android: Udacity
- Frequently need access to 'how do I do this thing that I know should take only 10 mins in app Y?' help: Lynda
- ELI5: Code School or Treehouse
- Anything teachable that's non-tech: Udemy
https://fedora.bitfountain.io/courses/android
It's normally $149 for lifetime access, but they runs sales on it as low as $49.
Coursera has some good stuff and it's free if you don't care about the cert. Their Functional Programming in Scala class is excellent.
I believe he still has those courses but he intially opted out of their discount program. A course he sold for $200 would have been sold for far less which undermined his own brand but also didn't give him a fair shot at earning from it, especially since he was helpful in responding to any questions I had.
I was lucky and took the course when it was $200, it shortly after went up to $300 due to changes in revenue sharing based around coupon codes. This also meant he stopped offering for free a really helpful free course on technical testing.
(The source of this information is through course announcements made at the time, I can publish them in full here.)
This post from udemy to instructors is interesting reading: https://blog.udemy.com/announcement/
One benefit of the udemy over the pluralsight model is that years later I still have access to the course and can revisit it, without paying an on-going subscription.
Pluralsight overall seems to have better content, at least from a software developer perspective.
As an example of a non technical class; The Secrets to Drawing on Udemy is Amazing. I am a (bad) hobby artist in my spare time and this class has done more to help me with my drawing skills than any other book or class I've tried in the past; my kids have been going through it too and they absolutely love it.
https://www.udemy.com/the-secrets-to-drawing/#/
This is two of the benefits of Udemy over Pluralsight
1) On Pluralsight I would never see this class (well not currently anyway) because it doesn't fall within their accepted domain of classes.
2) I paid the $30 one time for this class and I can go back and review whenever I want and let my kids go back and use it a year later and not have to pay another subscription fee.
This assumes that Udemy still exists at that time. The Udemy mobile apps allow offline caching, but the Udemy site does not allow you to download videos to store them permanently on your computer. An open source tool to help users do this themselves was served a DMCA notice: https://github.com/github/dmca/blob/master/2015-08-12-Udemy....
I also subscribe to the BGR Store mailing list which sends out notifications of discounted classes across a wide range of MOOC offerings. It's a bit tedious to wade through the emails, but it's worth it to keep track of the discounts available.