I do surveys via Survey Savvy. I haven't made a lot, because you have to answer pre-survey questions that can exclude you, but I find every little thing helps, and surveys can be just one of many things you do online. There is no cost to get started, but it does take some time to fill out your information. The more info you give them the more likely they are to send you surveys that you are qualified for. PM me for more details.
If you are looking to make a constant stream of income, I would look to several sources. I use what I make for extras or Birthday presents, ect.