How to reduce the cost of developing such a terminal?

Hello!

Have an idea to make small terminals for receiving payment (rate, values - 1,2,5,10,20,50,100,200 and 500).
Should be placed on the wall.
Need a small color screen (at least 10"), not necessarily the sensor.
Necessarily the presence of wireless adapters (normal 2g or 3g), i.e. the Internet via the SIM card. Although you can also consider the option with rj-45 port, but the network is not on all points...

The task following-the user chooses what to pay, making money, the payment gets to the server. Also, when you enable the terminal is naprashivaetsa some service old.. therefore, special requirements to the Internet - no. Well, maybe more (at the stage of debugging) in 3 hours the terminal will reset your screen to be able to identify bugs software))

At the moment, have chosen this option to take arduino, to it to connect a TFT display, 3g module separately, and a separate bill acceptor. And the case order of the usual iron that tint.
It turns out about $ 300 for the device... Prompt who-thread how to make it cheaper?
P. S. validation of bills not needed, only need the definition of the denomination... as a magazine for money fit the usual plastic box. No checks, keyboards, cameras, etc. are not required
June 5th 19 at 21:30
2 answers
June 5th 19 at 21:32
How to reduce the cost of developing such a terminal?


Get ready.

Google.
ready very much embedded iron that will not be used
Sense to overpay for him? - Jayce.Hyatt92 commented on June 5th 19 at 21:35
, on Google. There is something that you need.

Try googling in English, varying requests. - Assunta commented on June 5th 19 at 21:38
June 5th 19 at 21:34
How to reduce the cost of developing such a terminal?
Ready to buy b/y terminal for 200-1000 dollars, depending on condition.

Also interested in the question whether it is possible with the help of Arduino to build a normal GUI?
No.

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