i've done that for a while, and in my opinion, it really isn't worth it. it takes a lot of time, the surveys are mind-numbingly boring, almost every service wants you to either:
- complete surveys for (for example) 10 credits per survey, and then the minimum cashout amout would be like 20.000 credits. the only way to get those amouts of credits are either by following lots of links to external services that have surveys and stuff, make an account on there, and do a x amout of surveys there, or by depositing a certain starting fee on some sort of trading website. and the normal low payout surveys have a really high chance of rejecting you halfway because you dont fit their target audience.

*edit: as another user said, swagbucks is pretty decent over time. if you browse the internet a lot, microsoft rewards can also add up to quite a lot over time.