Without the keycaps all items to build the keyboard sum up to around 105 EUR / 125 USD. The aluminium plates for the Sandwich Case and of course the Cherry MX switches are the most expensive components.
- Circuit Board, 5 USD with EasyEDA
- Arduino Pro micro, 5 USD on eBay
- USB to Micro-USB cable, 2 USD on eBay
- USB to Mini-USB cable, 2 USD on eBay
- 4-pin Push Button, 1 USD at eBay
- Mini-USB port, 0.51 EUR at reichelt
- 68x Cherry MX Switches, 36.4 EUR at [reichelt](https://www.reichelt.de/Tastaturzubehoer/CHERRY-MX1A-G1NN/3/index.html?ACTION=3&GROUPID=8099&ARTIC