I'm not sure how scalable this is, but I get $10-15/hr tutoring through local connections and "tech support" (read: going to people's houses and running printer setup assistants or doing pricing research for them). The nice thing about both of these is that my employers treat me as high-status for being able to perform these tasks, because telling someone that their backup drive isn't broken and the alert they're getting is normal apparently makes you a magic-user.

I'm a high school student (read: no provable qualifications other than references), so if you have a reputation as being "good at x", that's probably enough to get a tutoring job for x, but it would only be a fraction of the hours you want.