Static not necessary; you can use a service such as dyndns.com to associate a name with a dynamic IP for the VPN.
The OS X built-in VPN is free, but requires changing some modem/router settings to port-forward VPN (and possibly FTP) services to the computer acting as a server. A service such as Hamachi costs money, but requires nearly zero set-up.
If you go the OS X VPN route, you can find sites to describe how to set it up manually from Terminal, you can purchase a helper app that makes the settings for you for around $25:
http://macserve.org.uk/projects/ivpn/
or you you can upgrade to a server version of OS X which provides a UI for setup. For Lion users, the upgrade to Lion Server is only $50 I think.
You can try LogMeIn's VPN product, called Hamachi for free and not deal with local machine setup, router setup (particularly if you are in a setting where you cannot change router settings) ... but if you want to keep using it, there are monthly/annual fees for commercial use.
https://secure.logmein.com/products/hamachi/licensing.aspx
Karl
Cheers,
Karl
AC 28 USA and earlier • macOS Sequoia 15.3.1, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB