Hi, as far as I know there is no such site , most of them advertise that for 10-20 dollars they will give you hundreds of active referrals but if it would be that easy most of us would have thousands of referrals and make huge profits for no work at all.
Someone posted a few days ago in the forum his experience with one of this websites Beware of the scams
There are also free ways that you can get referrals by advertising your link on blogs, forums or social media. Or you could buy advertising on other PTC websites but that's quite expensive . I've spend $20 on advertising my link on another ptc website and I got only 4 referrals from that and most of them are inactive so it's not a very good way of getting them.