I have been earning about $30 to $50 a week in Bitcoin by taking surveys on this website called Idle Empire. There are many ways to earn points on the platform. You can do surveys, play games online, watch videos and completing offers. You can spend about a half hour a day taking surveys alone and earn about $30 a week in Bitcoin. You can cash out via Paypal, Coinbase, Amazon and a dozen other methods. There is a small fee to cash out, about 5k points. You also get a bonus for being in the top 3 of earners each month. First place earns you an additional 300,000 Second 200,000 and Third place 100,000 points. You also get a bonus if you refer someone and they earn points, you get a % of whatever the total amount of points they earn per month. This does not effect their points at all.
If you really want to go beyond casual use on the site, you can make over $100 a month. I spend about 30-45 minuets a day on it. Looking on the leaderboard you see users making a lot.
To get started click this link to Idle-Empire and start earning Crypto currencies by doing surveys a few times a week.