How to earn even more from PTC sitesYou earn not only Cash but Points too (as a bonus) at some PTC sites by viewing ads. You get these Points for free.
You can then exchange these Points into Cash to Purchase balance.
And then you can buy Rented referrals from Purchase balance.
This way you get rented referrals for free.
You can extend these referrals for free too - again using Purchase balance

Or just set Autopay to Enable, it will extend your referrals automatically every day they click by 1 day.
The list of sites where you can rent referrals for free:and some more...