The price not only is determined by the time involved, but you also have to consider the detailed work. A smaller quilt, faster to make, but one of a kind, can be much more expensive than a larger one than can be easily reproduced. Also your market will determine the price. I have sold several in NYC for a lot more money that I could have gotten in northern NY. In some markets people are willing to pay what your work is worth and in others they just don't value it as much.