Ok my small business wants to list Applications which are high price - how much is MS going to charge me??
Assuming I can write a metro app to talk to the USB port to talk to the hardware which the Windows 8 app would coummicate to.
A good place to look at submitting apps and the prices would be
this page on MSDN. This page covers most of the questions you might have as a devloper selling an application through the Store. I hope this helps!