Honestly, it doesn't matter what others think it "should' cost, even the customer.
With yyour experience, I'm sure you have a fairly good idea how long the job will take. Multiply that time by what you need/want to make per hour. This is the hard part of the equation to get to in all honesty, but it will become easier thru time. Add ALL the material costs into the labor & you have the number.
I can't stress enough how important it is for you to quote work on what YOU need to make vs. what others think it should cost, or even what your competition would charge. You'll soon realize that everything else is irrelavent to YOUR business.
Lastly, sorry ot hear of your loss. I wish you the best of luck in carrying on, and hope you can succeed through the "crash course" of managing a business.