I have sold many quilts. Going from $35.00 for a fat quarter of a particular theme, with a border and stippled, to $600 for a queen size with a wolf panel in the center, nine patches around it and quilted with loops. I do all my work by machine. I am quick for my customers and even though I have a full time job and a life, I turn around the quilts very quickly. I do require at least 30 days for a deadline, and unless they require a very small quilt, will not commit to anything before 30 days.
Embridered quilts:
I made two baby quilts requested with embroidery in the center of the blocks, one with Elmo and one with Care Bears. When it comes to embroidery I have the customers pay separate for 50% of the cost chart. Not 100% because after I am done with them I still keep the pattern to use. If the customer wants a unique quilt and request that I don't use the pattern again, then I charge them them 100% of the pattern.
I mostly ge tthem at emblibrary.com.
When I do a craft show I tend to charge a little less, because the quilts are of my choice and the customers just come to buy. If some request a specifec quilt they are aware that there is a price that comes with a one of a kind quilt. I never stitch in the ditch, but if I did I would charge the same. They are buying your expertise and time as well as materials, and you know that good fabrics don't come cheap.
I don't have rule of thumb to charge for my quilts, but will not ask for any less than I would be willing to pay for them. I am not making myself rich with this, but it helps a lot, specially now that DH is laid off and no sign of a job for him any time soon. Maybe if I dedicated more time to it, but I need the benefits of my job and still want to enjoy sewing.
Maria