There is no "Firefox VPN". However there used to be a "Firefox Private Network" product until it ended on June 20th, 2023. https://support.mozilla.org/en-US/kb/firefox-private-network-no-longer-available If you mean "Mozilla VPN" then no it is not free to use. https://support.mozilla.org/en-US/kb/mozilla-vpn-free As for whether you can run Mozilla VPN on your device. https://support.mozilla.org/en-US/kb/mozilla-vpn-compatible-my-device