Currently I have 59 credits(I'm out around $3,000 for my education) and I am almost 19.
Straighterline is what I'm working with now.
Simply you pay $39 per course(an initial fee), and $100 per month. Finish a course within 6 months(you can finish one in a month easily enough) and you earn 3 credits. Sign up for as many courses as you want, finish them as quickly as you want.

Anyways I am doing Accounting 1(the material for accounting is nice, along with youtube), Precalculus, and English composition. They are my least favored subjects, and are a total pain to do.
However when they are done I can move onto my more desirable subjects that require far less effort on my end. I'll hopefully have my bachelor's degree well before I am 22.