A new Pi Zero is $5 if you live near a Micrcenter, which I don't. And than they have to have them in stock, which last time I was near one they did not. To that you also need to add a power supply and a micro SD card, both of which push the price up. And than you need a case, again, another cost. On the flip side, I have these nice looking fidgets that are, um, free.
Another thought, and it would not be great for places with a lot of dns lookups but great for a house, port the software over to an android app. You have power from AC, you have power from batteries, you have wifi and a nice display. And it is not hard to get old droids..