Check out Western Governors University. It is an accredited online university formed back in the 90's and I believe is non profit as well so it isn't like the University of Phoenix or those other scam schools.

They have a competency based model where if you can demonstrate competency by passing the test and/or completing the project you can be done with the class, whether that takes you 3 days or 3 months.

You also play a flat rate for the semester and complete as many classes as you want at a time.

I did it I loved it, I'd been in the field and was able to breeze through some of my courses while the ones I wasn't familiar with helped me.

They also have a lot of classes that the test is an industry cert, so it's a cheap way to get some certs under your belt as well.