APs

There are 4 things that will give you credit: AP, IB, CLEP, and dual enrollment.

You probably will not be able to take the AP exams if your school does not offer the courses because the school has to set it up with the college board to get the exam so people don't cheat. However, if there is a school near you that offers them, you could probably take the exams there. You would just have to contact the school. IB is similar.

However, if you are already self-studying, CLEP exams are a much better option. They are actually meant to be studied for not in a class as they are primarily marketed towards adults who aren't in school anymore. They are also easier, and probably cheaper than taking an AP exam internationally. Again, you will need to find a testing location.

The last option I think is the best option, which is dual enrollment. This means taking an online class with a college in the States for both high school and college credit at the same time. It will also increase your GPA just like AP if you make sure it meets your high school's requirements (talk to your HS counselor for this). You will take it in place of a high school class during the school day. These classes are usually much easier than AP's, but you still get all the benefits. However, they are also more expensive. The cheapest I've found is LeTourneau, which is about $90 per credit hour, which makes $270 for 3-credit hour courses, and $360 for 4-credit hour courses (with labs). I highly recommend LeTourneau's Dual Enrollment Program, specifically classes with Dr. Travis Pardo. There was one other college I found (whose name I can't remember) that had slightly cheaper dual enrollment, but had less options and my school would not give me the GPA boost because it didn't last for enough weeks. So if your school would recognize it, you might want to do more research on that. With dual enrollment, it is important to know how you will be getting your textbooks, as that can easily double the price. Amazon and Chegg are cheaper places to get them. Make sure those and lab kits get shipped to you before the classes start. My professors were fine with older editions. There is also a site called Library Genesis which provides free pdfs of textbooks, which you should make sure to stay far away from because they are trying to freely distribute information to people who can't afford to buy the textbooks, which clearly upsets the dynamic of power. Unfortunately, these pdfs work perfectly and are an easy and economical way of learning.

Anyways, I hope this helps. I know the struggles of being an international student with limited resources.