Calculating Min Selling Price

I can't relate that worksheet to your original question.

For any combination of fixed and variable costs like those that you described, the problem reduces to calculating a multiplier and offset. For your first example, multiplying direct cost by 1.4 and adding $2.80 covers shipping, fees, VAT, and 5% gross margin on the sell price. I don't follow the workbook you posted, but there is one pair of such numbers for each venue in which you sell.