The first step is to determine possible turnover
This should be done conservatively. Once this is determined, required resources and related costs should be taken into consideration. There are two groups of cost; fixed cost and variable cost, especially cost of sale.
Entrepreneurs often forget about fixed cost and set price according to cost of sale plus profit.
When fixed cost such as salaries and rent are then paid, a loss is made. Fixed cost should be distributed across the estimated amount of sales and added to the price. If this cannot be done without pushing the price too high for the market, there is no business to be had.