Screenly is a great digital signage application with both paid and open source editions. It runs on the inexpensive raspberry pi platform and can be setup and working very quickly.
There are benefits to the Pro(paid) version, but the Open-Source Edition(OSE) is very fully featured and can show you the capabilities of Screenly.
We have clients in many different industries using Screenly, including Healthcare, Retail and Entertainment.
Let us know if you would like more information about how digital signage can help you and your business.