You can even buy one of these ready-made boxes and slap on pfsense.

https://smile.amazon.com/Firewall-Appliance-Gigabit-Celeron-...

I use this exact model + RAM + mSATA drive and its more than powerful enough to sit in front of my SMB gigabit fiber connection while running DPI/OpenVPN/zabbix/etc.

pfsense is awesome and the learning curve is pretty reasonable if you understand basic network theory. I love it.