Raspberry Pi 3 B+ Raspbian may give you some insight if you are considering the Pi. Edge is a scaled-down ( less capable ) version of Ignition, which may also help with that word ‘inexpensive’. In general- the answer depends on: where the display would sit relative to your current Ignition gateway(s), and what resolution you need. Without that information, an inexpensive solution might not work for you. Note that the Pi solution may involve some additional software, as in the URL (link) above.