Maybe not the same thing you’re seeing, but hiding the margin in shipping fees is a common and time-honored technique on e-commerce sites like Amazon and eBay. Find any regular product, sort by price lowest-to-highest, and witness the number of very cheap items that look like an amazing deal… until you see the shipping charges. At which point it is as or often more expensive than the higher priced items + shipping.

It must be working on some unsuspecting shoppers because those listings are all over the place. There seems to be no policy against them either, and of course those items are never eligible for Prime shipping. To its credit, at least Amazon these days shows you the shipping costs on the product page itself, as opposed to finding out at checkout.