Ok, I get it.
You could have the nodeMCU host a simple web page which can be accessed from your local lan where the coin can be selected. The selection could be stored in eeprom (which is emulated using flash memory on esp8266) so that the selection is not lost if power is disconnected. Your sketch above already hosts a web page, which allows gpio pins to be controlled, so that could be extended to include the coin selection drop-down. The least user-friendly aspect of this for a non-technical user is knowing what IP address to connect to, but you have a display, so you could use that to guide the user, enabling them to access the page and select the coin option.