It seems that Amazon’s recommendations tend to steer their users toward their own products and partners instead of to best deals.
Recently, ProPublica conducted a research showing that Amazon’s pricing algorithms actually favor its own gear or gear of companies that pay for its Fulfilled by Amazon program, which would be fine if those are the best deals at the moment. However, it seems these algorithms do so even when the price is substantially higher.
It’s important to note that initial price doesn’t always equate the lowest price in practice. Many third parties on Amazon know how to lure shoppers in with a low price, but take forever to ship, may act rude when you have a problem, and so on.
However, the problem lies in the fact that Amazon’s behavior may be construed as anti-competitive, in the sense that its algorithms punish those merchants that can’t afford or don’t want to participate in Fulfilled by Amazon. This way Amazon gives a distorted view of options to its users.
Amazon justifies their algorithms saying that they’re designed to take into account the fact that the majority of its items are shipped for free if a person uses Prime option or the free shipping option.
Source: Engadget (https://www.engadget.com/2016/09/20/amazon-shopping-algorithm-study/)
The Wonderful World of Algorithms 