How Teleport App integrates Uber API?

First of all UberCENTRAL seems like not available in my country. I want to give my users free Uber rides to my stores directly from my website (web app, not native app), and there are 2 options:

• UberCENTRAL (not available for me)
• Teleport APP (http://teleportapp.co/ ,they use Uber API and it's +2$ per ride)

But I was reading the UberAPI and I can't find how to pay for my users rides. It seems like the API just works to make users pays for their rides, but I can't set up my code to do what Teleport APP does. Thanks in advice.