I have decided to try to learn Indonesian on my own, so I have a couple of questions. For starters, what (ideally free) resources are available to one who wants to learn Indonesian to college class level fluency? I am currently paying for college and my college does not offer a class on the language; I would highly prefer not to spend my money if it isn't needed.
Duolingo has an Indonesian course. I've found Duolingo helpful for learning a different language.
There's a 2000 Indonesian Words course on Memrise.
The Center for Southeast Asian Studies at the University of Wisconsin - Madison has a collection of online sources.
You can browse the indonesian tag on this site (not much at this point).
There is a wikibook, I've used it to bootstrap my learning process.
You can try online lessons with Italki, the teachers are darn cheap, and some are good. Be careful with your money, though, you won't see it again. What they call a "refund" is simply an option to book a lesson with another teacher. Read their terms of service carefully, they are quite draconian.
One more thing to consider: there's a lot of slang used, notably in chat apps. For that reason, an Indonesian teacher is necessary.
I'm not sure about the quality of Indonesian in Duolingo, but Spanish was completely useless (for instance, second person plural for verbs was ignored completely, as if it doesn't exist; very limited vocabulary up to the most "advanced" level; the vocabulary seemed to be prioritized by similarity to English rather than usage by native speakers - this reflects my impressions as of about 2015).
I've spent 7 weeks in Indonesia and speaking Bahasa Indonesia on daily basis after a few months of learning before the trip.