Due to the increasing popularity of metasearch, more and more similar websites are being created. However, some sites remain the most popular: Trivago, Kayak, HotelsCombined, Google Hotel Ads en TripAdvisor Instant Booking. Although the basics are the same, the payment model is different for these parties.
At Trivago, Kayak and HotelsCombined the hotelier has to pay per click (Cost Per Click), which means that you pay a (small) amount when a booker clicks on the price that links to your website.
With Google Hotel Ads and TripAdvisor Instant Booking, you pay per confirmed booking (Cost Per Acquisition). A good thing to keep in mind is that when the booker books directly with you, the visitor is not redirected to your hotel website, but the booking is processed in the metasearch platform itself.