Factors Google Search Uses to Rank Its Free Hotel Listings
Google said that "free booking links may resemble hotel ads, but they're not ads, and are ranked using a variety of signals to determine which links are best to show users." Google clearly said again that "no one can buy a better placement for free booking links," but explained "advertisers can bid to be ranked higher in the hotel ads section." Google also said that it "clearly mark ads" with the "Ads" badge in the hotel booking search results.
Google Search states that it uses several factors to determine the ranking of hotel listing, including consumer preference, value offered to the user, landing page experience, and historical accuracy of the prices provided to Google as measured in the Price Accuracy Policy.