To give buyers a better understanding of your store's potential, you should include your average profit margin in your listing. This is the percentage of profit you make after all your expenses are deducted from your total revenue.
The profit margin is displayed on your listing as a percentage. While most business' profit margins vary month to month and product to product, you should give buyers an idea of what your total margins are on average.
Calculating your profit margins is easier than it sounds. Take the total amount you spend each month to run the store and then divide that by the total amount you make in sales. Once you have that, multiply that number by 100 to get the percentage.