Yeah, but it's a lot nicer if you have a ticker on the wall like a digital clock of sorts... Ah well. I suppose the hardcore traders with tons of bitcoin would buy it even for 60-100$, but I wouldn't.
You can skip production costs, if you produce in another continent. For example, you can get one of this flying drone helicopters for about $10 in China (I have one). Of course, you have shipping costs;
Perhaps a simple serial/usb cable to a tiny board, with the LCD attached. Prints whatever data you send from the computer.
Here is a list of some cheap boards :
http://www.intorobotics.com/alternative-arduino-boards/Example prices:
MSP: USD $10
Teensy : USD $16.00
Funnel : USD $16.84
For example the MSP has input/output pins for easy integration of external devices. It does not come with an LCD screen tho. Im guessing the total cost would be around $20 to $25 to produce in the cheapest way possible using standard boards.
Alternatively, you could link the LCD screen directly to your computer and use computer software to interact with it. Assuming the LCD has some mico-controller attached to it.