Withdesignplaying such a crucialrole in thesuccessofdigitalsignage, the top-scoringexamples tended to focus onprovidingclear, legiblecontentonscreens integrated into architecture.
This strategy requires very visible signage, some nifty software that distinguishes the method of payment, and ultra-clear communication with customers about the reason for the difference so they don't feel they're being whacked unfairly.