I've read several responses. $800 is way too cheap in my opinion, especially for hand quilting. I agree that most people don't know all that goes into a quilt for material,supplies and labor.
I'm making a consignment quilt top now for a very large queen and figure the cost of material to be $400 (240 top, 70 back and 65 batting, $25 for thread and disposables). Since the quilt top is larger than my quiting machine is currently set up to handle, I have to pay someone to quilt it, which will be around $300 (custom). So before I even start working on it, the cost is $700.
I had heard the 3X rule before, but hadn't figured it out until now. Actually, that is pretty close to what I'm charging for mine. I'd charge extra since you are hand quilting!