Well, I tried all the usual things (washing cars, doing garden work, helping out, etc...), and honestly, it bought me barely anything - certainly not enough to justify an entire weekend of back breaking work. Some of my friends have tried to babysit, and to this point I think that only a handful have found and stuck to a couple of families that they're happy with in terms of working conditions and pay.
So after all of my frustrations in terms of making cash, I decided to go a different route. I was known amongst my friends to be pretty good with technology and electronics, so one day, someone came up to me and asked if I could repair their iPhone. Seeing as it was someone whom I knew fairly well, and that they didn't mind that I screw it up because of the relatively low price that I was doing it for (and the fact that they were getting a new one via insurance anyways), they let me try to fix it. I bought some parts super cheaply of ebay, and I fixed it for a tenth of the price apple asked for. Since then things grew, and I got my second customer within a couple of weeks. After about a year of doing this I found that getting parts from ebay took too long and did not justify the quality, so I found a direct supplier in China whom has prices that are only a fraction of what you find on ebay. So now I've been buying in bulk 200-400$ worth of parts every couple of weeks and making upwards of 1000$ per months (well at least in september, when everyone came to me after the holls) from just spending several evenings repairing each week. People say that I'm just lucky, but no, I just worked my *** off. All I started with was with the 10$ I got when I signed up for my debit card.
I've been repairing iDevices for almost 3 years.