For VPN’s there are a lot of options and different types out there but here i will focus on an on permise VPN server used to connect users to the internal network.
Free vs Paid
When it comes to price the only difference between a free open source solution and a paid one is that paid versions offer business support. So for non critical operations the open source option is definitively the best option financially.
You will find both options below.
Free (Open source)
Paid
The VPN feature is free but you have to buy a Windows Server License