Amazon Signage Stick and Fire TV
A small HDMI stick behind the TV you already have.
Amazon's Signage Stick is a supported Casty player. Plug it into the TV, set it up with the Amazon Signage phone app, then enter the pairing code it shows to connect it to Casty.
Fire TV Sticks that run Fire OS, which is based on Android, can run the Casty Android player installed by hand. They are consumer devices, so we check the model with you before you rely on one.
Good for a single screen on a small budget, such as one TV over the bar or in a cafe window.