Google Flight is a Meta Search Comparison Engine (or Aggregator), which does not sell any flights. This will compare thousands of options in one search and show you the best results. Then you will book your flight through the airline or through different OTA (online travel agent). This purchase will get commission from Google Flights. However, the price is similar to what you will get when you directly wave Google Flight as a 3rd party.
Google Flights – Search Cheap Flights Tickets on Google Flights