Mturk is a crowd source site where you get different tasks, when you complete the tasks within the time period then you get paid for completing the task.
There are simple tasks like
1. Google search, Facebook like, share twitter, YouTube comment etc.
2. Extracting data from a Shopping receipt .
3. Transcribing audio to text
4. Translating languages without using any software or google translate
and many more , tasks are paid from 0.01 to 50$ per task
Choose your task wisely earn more, all you need is a skill in that particular area .
The more you work the more you get.
Freelancer is another professional crowd source site where you have to create your profile and update your projects previously done. You have to complete small paid qualification tests to upgrade your skills to that the client will know about your skills.
In this site you have to browse the projects and bid according to the given charge per project.
you will have 10 bids for free.
upgrade your skills and bid projects ,get the project , complete it and get paid.