AFAICT only i386 and amd64 architectures are supported
Cheapest would be the $5 PC you find at Goodwill/a school surplus auction/is given freely to you/etc :P
dne: ARM is supported
mjp2: I see, that wasn't clear from https://www.pfsense.org/download/
what bout here? https://www.pfsense.org/products/
the first product is an ARM device :)
and the "Hardware Compatibility List" down the bottom
Up_the_irons : Happy Invoice Day!