Amazon MTurk is a portal where you can do micro jobs on the internet. Work available are those that cannot be automated including; transcription jobs, short surveys, categorizing tweets, signing up to programs, identifying objects on an image, recording videos, and data collection.
According to Sarah Kessler in her book "Gigged", the median hourly rate of a worker doing MTurk in the US is $4.65 while in India is around $1.65. This method does not promise huge earning potential (some websites even call it a sweatshop) but this is still a legitimate way to earn online that is why it ended up in this app.
Use Turkopticon to check the requester's profile and avoid requesters with a low fairness rating. These people may have the habit of giving low ratings for no good reason.
Mind the quality of your work and don't select jobs or HITs that you know nothing about.
As a beginner, it may take you up to an hour or more just to earn a dollar. The more you complete jobs the better you are qualified to see higher-paying jobs.