Easy Blacklisting, Admin to Unblock. Or Whitelist?

It would be nice if there was a general login for users of a network that they could login in and block websites, yet require an elevated, admin account to unblock them or make any other changes. Also. A 25 limit quota does not help. I would gladly pay for more. And not the 50, that paying will give you. I'm talking about like 1000 for a small fee. I don't have an enterprise, so I don't want to pay enterprise prices. I just need a good blacklist, not all the additional options. In other news; the best thing would be a whitelist option with a pre-configured list of known safe sites. Does such a thing exist? Can it?