Just let your friends know there are no 'rare' colours in Staffords, they shouldn't pay more for any colour. Stay clear of such 'breeders'.
There are plenty of good breeders out there, best usually to go through your local breed club, get the number of the secretary and she/he should know which responsible members have puppies or are expecting them.
Ref the breeding and silly money for blues it's much worse in the UK - how or why people pay the money and are taken in by the whole issue is beyond belief they are normally advertised as rare and yet there are hundreds and hundreds of ads for them, most it has to said bare little resemblance to what a Stafford should look like.
As with any breed, research, research research and then make an informed decision.
Good luck with your search, it's a truely wonderful breed and there is no other dog I want on the end of my bed