Several manufacturers have 2- or 4 port small form factor system-on-a-chip solutions. A Celeron J1900 can route gigabit network traffic at near line speed unless you do a lot of packet inspection or terminate a VPN in the router. Those can be had for $150. Anything newer will be more expensive, but also more capable/more future proof.
Just make sure the system has Intel brand network interfaces if you want to run pfSense.
Combine with wireless access points of your choice rather than opting for an all-in-one solution for best results and longevity.
I also want to support the pfSense project ;-)
I'm also thinking about supporting the local economy and buying an APU2 from PC Engines.
Their customer support was great. I owned the predecessor of the ALIX and when it broke, I ordered the ALIX.
I then tried the PSU of the ALIX at the old board and it still worked (but I wanted the new one anyway).
I told them about this and they sent another PSU for free, without me even asking for it.
And I do use external APs. Currently an Airport Express (not the latest revision). If I had a house or a bigger apartment, I'd go for Ubiquity.