I think the sites that offer the most CC freerolls take the prize. For sheer numbers of CC tournaments (many of them platinum) at this moment I would say PS. Of course CC freerolls are evolving.
I think that the best poker site with freerolls was ACR, especially when they held tournaments with streamers and in those tournaments the prize pool was almost always $20,000 and those who played them constantly won thousands of dollars. Now the best site is 888 Poker
888 poker. Refers to a proven classic for beginners and offers a standard set of poker disciplines with the lowest rates. Almost all bonuses are tailored for those who have recently played poker: the prize fund of most promotions is played in freerolls with access by task.
888
This is a reliable and safe site that offers its players a simply huge number of daily freerolls. It's really not difficult to build a bankroll on this site.