The markup from the wholesale price you pay for goods to the retail price at which you sell those goods is the lifeblood of your business. You want to set prices that are competitive and at the same time make enough profit margin to cover your costs and leave a profit for the business.s a percentage, the profit margin is 15 divided by 25, or 60 percent. Profit margin is always calculated from the retail price and is the money coming in to run your business.