As a Usability Hub https://usabilityhub.com/ tester, you'll give feed back to Web designers/owners on various things. It is possibly the easiest way to earn online.
To learn about the types of tests you may encounter go here https://usabilityhub.com/guides
You will need : a verified Paypal account
basic computer skills. They'll ask about your level of knowledge in computers, I guess it's so they can provide you with tests that you can handle. But, you don't have to be an expert.
Pay out minimum is 100 pts. 100 pts = $10.00
Advice for ya? When responding to say a preference test, be honest and be thorough. They don't want vague answers about how you like the pretty colors. This is super important. The answers you give will determine how often you receive tests. More tests = more money= faster payout.
Don't expect too much in the beginning. When I first started out, the first three days they sent one test each day. Then I started to get a little more after that.
Week days are the best time for tests. Weekends are slow and you'll be lucky to get anything at all.
As you can see here I haven't reached payout yet, but I'm almost there. :)
This is not a quit your job sort of deal. This is gas money, a little beer money, oh Kroger is having a 10 for $10 sale on peanut butter because we all need 10 jars of peanut butter kind of thing.
Sorry no reference links to share.