Thats a good price. Cheaper than the $6000 radial arm you'll need to slice the mitres on extrusion sticks, a three phase electrical connection for it, a UL inspector in your pocket monthly, a qualified guy to put it all together (and all of his costly baggage).
If you leave money on the table just to get the job you will lose respect of fellow
sign guys, muddy the waters of the industry, and hand over free money to the customer who would have had to pay the price anyway.
Double that price, add design charges, graphic charges, delivery, install, and permit costs (not just permit fees, all labor costs to obtain the permits plus the fees).
Best of luck to you with the job.