The price at which a product is purchased from China is $25. The actual retail price of the product at a Wal-Mart store is $36. If a 12% discount is being offered, the prize at which the product is being sold is 36*(1 - 0.12) = $31.68
The credit card company deducts 3.2% for the use of its payment gateway. The cost incurred per item is $31.68*0.032 = 1.01376.
The cash inflow for each item sold is 31.68 - 1.01376 = 30.66624. The profit made is 5.66624. This is 22.66% of the price at which the item is procured from China.
Wal-Mart makes a 22.66% profit on the sale of the product