On this website, you can choose between one of three plans. The first two plans are just study aids for students taking the class. But the third option allows you to use the website to actually test out of entire college classes (everything from freshman to senior level classes).
So far, I have tested out of Principles of Management, Principles of Marketing, and Principles of Finance (all considered junior level courses). For $200/month, you can take up to two exams per month. That means, if you tested out of two classes per month, you would be earning college credit at a rate of $100 per course. You takes these tests online from the comfort of your home (they are proctored online so you do need a working mic and webcam as well as an ID). It's a pretty sweet and simple deal.
Earn college credit here in 16 weeks and spend thousands...
or here in two weeks and spend a hundred bucks...
The main word of caution is to check with your college before subscribing to study.com. If your college does not accept study.com tests as credit, taking these courses will be mostly a waste of time. (You'll still learn a lot from them, but you will have to take the class again at your university to earn credit.) A lot of colleges won't accept these credits because it takes money out of their pocket and gets you off their campus sooner. So if your college does not accept these credits but you want to test out of enough courses, you may need to consider changing colleges.
If you are in college for the social experience, study.com is not for you. If you have test anxiety, study.com probably is not for you. If you like to spend 16 weeks sitting in lecture halls learning about things you already know something about, study.com is not for you. If you love taking out student loans and/or paying 3-15x what you need to pay to take a class, study.com is definitely not for you.
But if you are working full time, hate to waste time on subjects you already know about, love to save money, and/or you want to get your college degree knocked out as quickly as possible, study.com is definitely for you. This is the quickest and cheapest way I have found to earn upper level college credit in particular.
Let me know if you have any questions because I may be study.com's biggest fan. If you want to sign up, use the link above for a discount and I will get a little discount too.