Amazon is great at capitalism. The ubiquitous online retailer uses every psychological trick imaginable (and some we probably can’t imagine) to maximize its profits, and one of the most powerful tools in the company’s arsenal is price-controlling during sales like its Prime Day promotions. The next one is expected in mid-July.

Broadly speaking, Prime Day is all about convincing consumers to buy things they don’t need. One of the specific methods they use to do this is manipulating prices to make you feel like you’re saving more money than you actually are. (For more information, read this article where Amazon goes into more detail about their tactics.)

Of course, there’s a lot that goes into how Amazon sets its prices – inflation, supply and demand, and so on – but “making you think you’re getting a great deal” is a clear motivator during promotions like Prime Day. To be fair, this isn’t new, and the tactic is used by most/all retailers, but judging by their success, Amazon seems to be particularly good at it.

Consumers who want to buy things that are worth the price have at their disposal a powerful and easy-to-use weapon that was virtually impossible before the advent of the Internet: the ability to easily check the price history of a product.