One of the largest free dating websites out there, Plenty of Fish, has announced it will be introducing a paid for option for membership. You will still be able to join and communicate for free but it seems like members who pay will get featured and higlighted when people run searches for dating profiles. If you do pay, a 'serious dater' badge will appear next your profile, so people will know you've paid up and are therefore unlikely to be a time waster - you can read about the change here