Sorting a marketplace search by relevance rarely puts the cheapest item first. The ordering is optimising for something other than price, and knowing what changes how you use it.
The objective is revenue per search, not lowest cost
A marketplace earns a share of each sale plus advertising income. Its ranking system is tuned to maximise the value it extracts from each search that a shopper performs.
An item that converts reliably at a middling price is worth more to the platform than a cheap item that people look at and abandon.
So historical conversion rate carries enormous weight. Products that have sold well from this query before are shown again, which makes the ranking self-reinforcing.
Sponsored positions sit inside the results
Several of the top slots are usually purchased. They are labelled, but the label is small and the layout is otherwise identical to organic results.
Advertising cost is funded from margin, so sellers who bid heavily are often not the cheapest. Paid prominence and low price tend to pull in opposite directions.
The practical consequence is that scrolling past the first screen frequently finds better value, because that is where the unpaid ordering begins.
Fulfilment speed is treated as a quality signal
Items that ship fast from the platform's own warehouses are promoted, partly because fast delivery raises the chance a shopper completes the purchase.
Sellers who ship themselves, often more cheaply, are ranked lower for a reason unrelated to the product itself.
A slower option at a lower price may be perfectly acceptable to you, but the ranking has already decided it is worse before you see it.
Review counts favour incumbents
Ranking leans on the number of reviews as well as the average score. A long-established listing carries an advantage a new one cannot quickly overcome.
That is why sellers value control of an existing catalogue page so highly, and why review histories are sometimes attached to products that have quietly changed.
A high rating on thousands of reviews may describe an earlier version of the item rather than the one in the box today.
Sorting explicitly by price behaves differently
Switching the sort to price ascending disables most of the ranking logic and shows a straightforward ordering, which is why the results often look unfamiliar.
What appears at the top is frequently accessories, spare parts or tiny quantities that matched the query loosely. The filter needs tightening rather than abandoning.
Used with category filters and a minimum review threshold, the price sort is the only view that answers the question most shoppers think they are asking.