Implementing a data indicator with WiFi?

Question

WiFi

Hello everyone, I am faced with the task of implementing one system. There is a car dealership, which has a fairly large area where cars are for sale. There are a lot of cars, we will consider at least 100. The salon can review the cost of cars several times a week and change the price accordingly. The price should be under the windshield of every car. Previously, every time a person walked and changed the printed sheets with the price and data. Now a QR code has been printed on the data sheet, by scanning which you can see the price on the Internet, but this is a bad decision, because not everyone has the Internet and not everyone understands what needs to be done to find out the price.
There is an idea to put an indicator on each car, which will display at least the cost of the car. The indicator must be connected via wifi or in any other way to the control panel, from where it will be possible to set a price for each car, which in turn will be displayed on the indicator.
You can do it on raspberry, but it's expensive and you need external power, which is highly undesirable. Maybe someone has experienced similar things and could recommend a solution to the problem? In principle, a ready-made system is not needed, the main thing is an indicator with a connection and that it be sufficiently budgetary. We will write a control system for all this ourselves.
UPD. Thank you all very much. Indeed, there are ready-made solutions.

Answer 1

There are ready-made solutions, google on "electronic price tags". Start digging in this direction.

Answer 2

No need to invent what has already been invented before us. In trade, there has long been an "electronic price tag system" (ESL), any screen sizes (TFT / E-ink) ,
zigbee / Wi-FI control, etc.
and for what - no matter what price they name, it's still cheaper than reinventing.