Most reliable thing I've found for a quick buck is to get something on your computer many people want (eg: a game), upload it somewhere and use one of those link shorteners that pay for every time it's clicked. Doesn't pay much, but for some quick cash it can be very worthwhile! For example, there was an update for a game on the 3DS that many people didn't know how to get, made a CIA of it and uploaded it, 2 days later and 4000 clicks, I had about 4€. If you can find something a LOT of people want, do it like that, it's worth it! You won't get much, but it works.