It's not quite the same thing but when I worked at a beading store about a decade ago, the people who made jewelry calculated $5 for every hour of labor and doubled the cost of materials when pricing. They also factored in the price of comparable items and the difficulty of making the piece into the final price.
3b/c, medium-coarse, low porosity, high density
HG: Jessicurl Too Shea and Kinky Curly Curling Custard
Shampoo: nonsulfate shampoo and Suave Naturals sulfate shampoo when needed