buyhitscheap.com is the site that sends me traffic without myself buying any traffic package from them. I don't know how I get traffic from them. I can't sit back saying that all free traffic are bonus. Such traffic are not allowed in adsense websites. Though I don't have adsense in this site, I have adsense ads in other websites and I am confused how I'll manage if I get traffic from this source for those adsense sites. They send me some 2 or 3 traffic regularly.
see if there is a forum or blog on there with someone linking to you. Also, contacting the admin might help.