Below are list prices for Viking's VK158 dry pendent sprinklers in lengths of 6", 12", 18" and 24".
Temperature's don't impact; the price for a 286 Deg sprinkler is exactly the same as a 155 Deg sprinkler.
As I said these are list prices and I would suspect a contractor's net price will be a multplier of between 0.25 and 0.30. In other words the list price of a 6" dry pendent is $204.18 but I would suspect the net price to a contractor will be somewhere around 0.30*204.18=$61.25 each.
VK158 SR REC PD CH 155 6 Viking VK158 $204.18
VK158 SR REC PD WT 175 12 Viking VK158 $230.09
VK158 SR REC PD WT 200 18 Viking VK158 $261.70
VK158 SR REC PD CH 155 24 Viking VK158 $293.34
When I am bidding work I generally use $75.00/head which pretty much covers me.
And then there are the special dry pendents such as the Viking VK504 K16.8 ESFR dry pendent that carries a list price of $1,414.94.
VK504 K16.8 ESFR NPT165 36.5" Viking VK504 $1,413.94
Even with a multiplier of .30 it's still a pricey head at $424.20 each when you got a job having 1,200 of these things.
These prices do not include freight nor do they include sales taxes.
And then there is the wait time for non-typical lengths and you can easily wait one to three weeks for non-standard lengths of dry pendent. Nothing a contractor can really do about this.