One of my favorites- you study independently using whatever resources you like, and when you’ve learned the content, you take the test. Colleges differ in which exam programs they participate in as well as the number of credits awarded or passing score, but the details are less important than the opportunity. A good strategy is to simply bring a credit by exam opportunity into your homeschool following EVERY homeschool course you teach.
While this list below is for ONE specific college, it serves as an EXCELLENT catalog to demonstrate the exams available in various subjects. As a rule of thumb, it costs only about $100 to take most credit by exam options, except for CLEP, which you can do right now for free via Modern States.
When you earn credit by exam, the exam “replaces” the need to take (and pay for) the class later in college. I used credit by exam to test of out an entire associate’s degree just for the fun of it. You don’t have to be so extreme though! A few tests = save lots of time and lost of $$$$!