I too charge .015 per square inch, which seems to be a common price in most places, other than larger cities (I'm in a rural area too). When the price is as low as you quote, I would be careful of the quality. Some LA quilters only have a few low density patterns, and you get what they happen to be in the mood to do that week, not necessarily a pattern that will enhance YOUR quilt top. They may only offer one or two colors of thread. They may not baste down the edges of the quilt as they work. (Yes, basting takes more time (more time = more $$), but it ensures that your finished quilt is square and straight.) Their stitch length may be uneven or too long (toe catchers! LOL). Their tension may be unbalanced. Is the quilt loaded and advanced carefully so there are no pleats or puckers on the backing when they are finished? When the thread breaks or bobbin runs out in the middle of a design, do they unpick enough to hide the new starting place, or just double stitch on top of the break for a half-inch or so? Do they have business insurance in case something happens to the quilts in their care?
If you just want the three layers of the quilt held together, and don't care about the items mentioned above, then it may be a good deal. Ask to see samples of their work, and if you do decide to try them, give them one top, something you don't care much about, to see how well you like their work.
Andi