Connect tour operators to the travel site through the API

There are contracts with tour operators, Coraltravel, TUI, etc.

The template for the site is selected as follows:
https://demo2.pavothemes.com/triply/home-2/
https://demo2.pavothemes.com/triply/tours-list-sidebar/
https://demo2.pavothemes.com/triply/to_book/buenos-aires-calafate-chalten-ushuaia/

How much will it cost on average to connect one tour operator (API) to the site? The total number of operators will be about 5.