I have the bits for the kit available now but I am not in a position to actually sell them yet…..
I put together the kit for a local group and based on this the price for a complete kit is around USD 50.00. Includes all the parts required for the actual device (including the Arduino and the Bluetooth module). Does not include a power supply, leads, valves, etc.
The power supply should match the valves you use and have a 5.5mm/2.1mm connector.
You will need to assemble the kit yourself so you will need soldering tools.
I can get Shako valves but I would probably not be the cheapest place to buy from. Depending on where you are there should be a local supplier. (Based on a quick look my price would be around USD 30-35. No idea what the postage would be though.)
I have sent you an email with additional details. If you are interested please let me know by email.