Looks like pricing will be ~1.47 per prism. (Subject to change if costs change with manufacturer)
No BE controller included since its been causing you more grief than it's worth.

A USB interface will be provided which you can connect to anything capable of running cgminer.

Based on my experience with ASICMiner chips through USB interface, I do not recommend rPi for set it and forget it operations.  Consider a cubieboard A10 or any system that does not have Pi's USB bus limitations.

However, you can always run on a Pi if you wish, that's up to you.

Payment addy will be in OP, I do not PM payment addresses.