Wireguard is free vpn For linux 

WireGuard: An efficient and a relatively new VPN protocol in the present generation. WireGuard server can also be installed directly on a VPS or on a Raspberry Pi computer. This makes you have full authority and secrecy.  

Here are some pros and cons of wireguard.

Pros: Great privacy, ability to change where to work whenever needed, more beneficial in the long run.

Cons: Calls for professional input when installing and when making modifications in the system.