I agree, I don't think price is relevant, it is whether you are happy with what you have received.
+1.
It's fair enough that buyers shouldn't need to specify a price, prices always vary depending on stock prices, buyers spending habits with the trader etc.
Having said that I've just booked in for a P2 with DMS based on feedback on here and their published prices
It's the level of service that's the important thing, as Stew said most people are capable of googling prices and/or 'phoning around traders.