OpinionBar has no referral scheme, but the payment per survey is reasonable: I usually get offered around £1.00 for a short survey. I don’t know the US payment rates.
Once you have signed up, you will receive survey offers in your email. I’ve been getting these frequently, but it is a scatter-gun approach and you will often be screened out early on. It is worth being selective about which ones you choose to answer. Some of their surveys have been multipart, so completing one leads to a set of further surveys for extra payment. I’ve never had problems being paid by them, so thought it might be interesting to a few people here.