What do you mean specifically by paid privacy tier? Mozilla offers some privacy oriented paid services... one comment here mentions VPN, then there is Monitor Plus for online data scrubbing, Firefox Relay for message masking, just from the top of my head
To add to that, privacy features that can be offered for free, like tracking protection in Firefox, often are, and thus are available to everyone. Services like Relay, VPN and Monitor Plus, which require upkeep of infrastructure, are paid or have paid tiers.
(Disclosure: I worked on both Relay and Monitor, but this is my own interpretation; I don't set pricing strategy.)
