Comment by xnyan

> less than the cost of one of these Pis to acquire all of them together.

Before RAM went crazy, the Pi 4 was $75 for *8GB and $125 for 16GB.

Another consideration is heat and power consumption, I have an OptiPlex micro (also surplus) and power consumption is 8W-90W (standby versus peak), 5x-10x more than a Pi 4.