Why does Firefox mention a free VPN with 50 GB monthly usage, but when I try to use it I am required to subscribe first?

https://support.mozilla.org/en-US/kb/built-in-vpn There is the built-in VPN in desktop Firefox currently rolled out in the US, UK, Germany, France and Canada. It may not be available to you yet, even if you’re in one of these locations, as the staged rollout takes time to reach everyone. It is reportedly being rolled out in 22 additional locations for the Fx 152.0 release. If you are currently subscribed to Mozilla VPN then you should not use both at the same time. https://support.mozilla.org/en-US/kb/built-in-vpn#w_what-if-i-subscribe-to-mozilla-vpn