You need to take in account your time (set-up), thread, and electricity. If a mistake is made, you have to correct it which takes time.
LAQ charge by the square inch, meandering, $.015 to $.045; panograph-edge to edge all over design, $.015 to $.045; custom quilting start at $.05 per square inch. Also a thread charge starting at $5 for each quilt. This quilt shop charges a minimum fee of $35 for all edge to edge quilts and $75 for custom projects. They also charge for squaring backing $15; squaring up quilt top $25; pressing $25/hour; piecing backing $10 per seam. Adding strips to sides of backing due to backing being too small $10 per seam.
I took this from my local quilt shop.
Don't cut yourself short on cost.