There are two books on the market in regards to this. One is Sylvia Landman's Make money quilting & the other is Quilting for fun & profit. Her guidelines are Labor + Material + cost of material + profit = price. She suggest a profit of 15%. Also, another suggestion of hers is to charge by the square foot. For a simple twin pattern, I charge $13.00 per square foot = $585 for a typical twin size. Hope this helps.