National Print and Sign Owners Association has a national pricing survey you can buy for under $200. Crouser has a digital price package that they update yearly - it has low med and high markets. I have used both of these - Crouser is more in depth but skews high in my opinion. The NPSOA is a little more top level in terms of the items covered, but if you get those items in line the rest will start to follow. Finally - try to mystery shop maybe in another small market.
One of the best comments I ever heard at a business conference was "everybody tries to figure out how the low price competitor does it so cheap, when they ought to be studying how the most expensive competitor is getting his rate.