A one year renewal of the Comprehensive Gateway Security Suite Bundle is about $300.
That bundle gets you all the goodies, web content filtering, P2P blocking and 27x7 support.
If you are not using those features, Dynamic Support 24X7 is $125.
Add to that about 1 hour of time (really on 10 minutes) to install the license.
Those are not unreasonable costs. Yes, they add up over time, but that is part of op ex.
If you go the pfSense route, which is a fantastic solution, your costs are going to be higher.
You will have to invest 20 to 40 hours of labour to build out the hardware, replicate the rules in the SW, test, validate and swap.
You can get support for pfSense
If you use an old PC, rip out the HD and run from a USB stick. Old PC have old HD which are closing in on their life expectancy.
If you want something slick, look at Netgate and Soekris.
My 2 cents...