Retail arbitrage is a simple business model. First, a retailer sells a product for a certain price. Second, you purchase that product and resell it for a higher price. Third, you keep the profit. It doesn't matter if that product is being sold online or in-store. What matters is that the price it's being sold for allows you to make a profit through reselling.But even if retail arbitrage looks like a simple process of reselling products, it's not all...