@oguruma
First place I would have a look at the Netgate store if there
will be something (devices) matching your needs or according to your whole situation. If not you could;
Devices from the Netgate store
Qotom mini PCs on Alibaba
HSIPC devices on amazon.xy
older Intel J1900 devices on eBay
used Atom till Xeon E3 servers at eBay or refurbished elsewhere
There will be for sure something that is matching your budget and fitting your needs. But without knowing
your entire use case or installation you will do, we are all
only doing guesswork here. So perhaps you may provide us with some more informations about your usage case!?
Internet speed, provider
DSL, VDSL, Fiber,.....
Packets for installation like snort, Squid & SquidGuard,
pfBlocker-NG, ClamAV, cellular,.......
OpnVPN, WireGuard or plain IPSec?