Techtalks: Traveltech

Hi!

I have a question in regards to the Payment Processing models or actual setups that are used by OTAs. I am not talking about Booking.com or Expedia, it's mostly a question of how new and smaller OTAs set up their payment procedures.
For example, when a customer books a trip on the "Random Travel" website, the customer's credit card gets charged by the travel agency and then the payment goes to the actual property or an airline, right?

What are the other options?
And what payment processors can be used by the OTA to charge their customers?

For example, Stripe charges 2.9%+ 0.30c for every transaction, and +1% for every international transaction. This is a lot of money for small OTAs, since the commission is also shared with the Host agency. So if we take an example of a $100 hotel booking, the commission is 10%, in most cases, which is $10. Will say Host agency takes 30% of the commission, that's $3. Stripe takes 2.9% of the entire amount paid, which is another $3.
In the end of the day, the agency is left with $3-4 commission.

So my question is: what are the ways to set up an efficient payment process and what could be the options?

Sorry for the long question. It's really something I am trying to understand.