I'd go the mini PC/sff route, on eBay for instance you can get like a HP EliteDesk 800 G3 for around 50-80$ depending if you want a drive and adapter included think that's the best bang for the buck. I would've recommended buying a 20-30$ onn android TV box but seeing how restricted android tv is from another post kinda made me rethink that.
Edit: also if you can wait like a year more I bet the market will be flooded with cheap mini/sff desktops.