This.
No matter what the job is, it's simple math in understanding on what it costs to manufacture, what overheads you have and how much you need to make on the job.
There's absolutely nothing wrong with looking at what others charge as some products have higher premiums and some have small margins.
Also those smaller shops comparing to the big shops is really a no-no.
Different overheads, different equipment. etc. Your 2 person shop could produce 20
signs in a day, another shop could do 200 with 5 people