I personally like this one for some spare cash. It does not take much to earn an extra $20 – $50 a week. Some claim that they are able to make a living by dedicating their time to different jobs at mTurk. You will have to go through a learning curve, but once you get comfortable, you will find plenty of good and interesting HITs (Human Intelligence Tasks) to work on.
One of the most underrated freelancing sites ever. The site started as a place where you could get paid to do short tasks for just five bucks. Over the years, it has slowly morphed into one of the biggest gig/freelancing sites where you can now charge any amount to do all kinds of stuff for other peoples. Anything from serious stuff like copywriting, translation, voice over social media management to silly stuff like prank calls and everything in between.