How will I get paid for taking a survey, and who will pay me?

It depends, but the important thing is that you'll know the exact details up-front before taking a survey.

For example, sometimes you'll be paid by the market research company who is conducting the survey on behalf of a client (usually big Fortune 500 companies, but not always). Other times the company that developed the survey - the company that directly wants your opinions - will pay you directly.

Payment methods vary from company to company but most will pay via gift cards. 

Again, the important thing is that you'll be presented with the details before each survey and you decide if you want to participate or not. If you do, you'll provide your payment info as part of the survey process.