For the sub-$100 price point, you often can't beat discarded thin clients. There's a steady of stream of units always hitting eBay, including ARM ones like the

For the sub-$100 price point, you often can't beat discarded thin clients. There's a steady of stream of units always hitting eBay, including ARM ones like the HP T-series and x86 ones like Dell Wyse units. If you really just need something that comes with a case and power supply, might already have wifi, and has a few USB2 ports to plug things into, these are great options.