Amazon does allow arbitrage, in fact, they welcome it. They have a policy which is essentially you can sell anything you want (within reason) on Amazon. For example, you want to avoid products that are only allowed to be sold through authorized resellers, and avoiding selling counterfeit products for obvious reasons. The term "arbitrage" has been around for a long time and is usually associated with the financial markets. A simple example of "retail arbitrage" is you purchase a product through a major retail store, such as Wal-Mart, Target, Wayfair, etc. and then you sell the same product online or locally at a higher price. The difference between what you paid for the product and what you sell it for is your profit. This is also true in the book trades market. Often, the product never touches your hand and you simply have the product routed to the buyer from the retail chain. It makes it far easier and also improves your profit margins.