$0.45 per bill? Surely that wasn't the shipped price you were looking for - stamps alone are 0.44 each... On top of that, it's a very labor intensive service.
Metered mail costs significantly less than stamped mail. A quick check with the USPS suggests a price of $0.237 per piece. That makes $0.45 per piece pretty reasonable for a fully automated service, assuming a human never needs to touch individual pieces of mail.
Fair point about metered stuff. I'd assume that it'd be extremely hard to automate this unless it was constrained to one or a couple of types of mail, though.
