There are a lot of cheaper alternative options for SBC than the Raspberry Pi lineup.
I was thinking of trying something from Banana Pi or Orange Pi.
In particular a Banana Pi m2 Zero
Orange Pi One Plus
Orange Pi Zero Plus
Orange Pi Zero Plus 2 + exp board
(any of the Orange Pi H5 boards really)
Is there a support list of SBC or known working SBC used with Octoprint?