What are the easiest APs to self-study?

Answered

Each person will give a different answer to this because some students are more STEM-focused and zip through the sciences and math. Others struggle with English and History and Languages. For some students, AP Lang or AP Lit would be pulling teeth and much harder to self-study than AP Calc A/B or AP Bio.

The easiest one to self-study would be an AP Language choice that aligns with the language you speak at home. So if you speak French, Spanish, Chinese, etc, then self-study for AP French or AP Spanish, or AP Chinese. However, if you don't speak these languages, and haven't taken at least 3 years of that language prior to taking the AP version, you have a very high probability of getting a super low score on the AP test.

The same goes for any AP course which is the culmination or lower series of classes that are pre-requisites. So If you haven't taken a bunch of art classes, you really should take AP Studio Art. If you are not a musician, then you shouldn't take any APs that have to do with Music theory. And if you haven't taking Bio, Chem then you shouldn't really attempt to take AP Bio, AP Chem or AP Environmental Science.

If you haven't taken a basic history class in US History or World History, then taking AP US History, AP Government & Politics, and AP World or AP Euro History will be challenging.

Some subjects like AP Micro and AP Macro and AP Psychology or AP Computer Science don't really require pre-requisites so those might be ones to self-study.

As far as FREE AP coursework, I don't know if there is anything except Khan Academy. I think you can check out various AP study guides from your local library. And if you want more flexibility, I would just order the Barrons Study Guides or something similar on Amazon and have the books delivered to you. They are only about $20-25. If you are on a budget you can find USED copies at various online book stores including eBay.

Good luck.