I do many shows and I usually base my pricing on a formula. whatever it costs for your product, multiply that times four and that's your price. Of course, you also have to factor in overhead costs. I use a flat ten percent for that. So the formula looks like this: cost of item times 1.10 to get factored cost. Then take that times four for your actual sale price. If it costs one dollar for supplies, take that times 1.10=$1.10, then take that time four=$4.40 for the sale price of the item. Does this make sense?