Market research outside your organisation

Does anyone have any experience with a good source of survey participants for surveys?

We have recently tried paid participants from a particular well-known survey provider and I have spent more time filtering spam than actually analysing valid responses. There is the obvious spam with random words, jibberish or a bot entering text that may match the question but really badly then there are the people who enter the bare minimum to get the money. The whole experience was really disappointing.