I think with Azure the costs for basic compute services are about the same, you can run the same code on Iaas (Virtual Machines) or Paas (Cloud Services, App Services) and the costs are the same for equivalent performance.

For more complex products it's probably different, but the value of that is also higher. Just clicking Azure Search and simply start using it is a lot simpler then setting up your own Elastic Search cluster and having to manage it.