You can definitely get OK used laptops for $75, that's why I asked that particular clarifying question. I'm wondering if they have any specific models or deals in mind, ideally with a link to an online retailer.
Think that'd make a better server than a Raspberry Pi 4 for the price? It's nice that it includes a built-in battery backup, plus screen/mouse/keyboard for initial setup and later debugging. On the down side, it takes up more space.