I got an 1 gig Orange pi zero 2 with a 2 port USB expansion board. I got it from ali express with a 32gigabyte micro SD card, USB to USBC charging cable for like $40.

I 3d printed a case for it. Provisioned it with a heatsink, fan, 18W USB power supply, and a UPS.

I use it as an octoprint server, the extra USB ports go to a webcam and a fan if i feel like it. It’s been reliable but I’ve only had it a month. Transferring jobs is nearly instant plugged into gigabit ethernet. Transfer is via API key not web interface. Seems to do alright in the CPU department. It has to parse some of the larger jobs for a minute.

Prints perfectly. Only had one resent packet USB packet so far. After it prints rendering out 1080P time-lapses was slow. It would hit like 70% cpu usage and take hours. Rendering out 1080P octolapses with fewer frames and less movement would hit 98% cpu use but be done very fast - like 10 min.

They just announced an orange pi zero 3 with a similar form factor (but not exactly the same) and larger faster memory.