In short, I think it would be a mighty fine addition, if not already planned, to enable at least a modal-based payment system for the purchase of experience-exclusive content and/or services.
By this I mean to say that if someone wants to let a 'subscriber' to their experience/scene have increased permissions (like in the case of, say, an RPG or other environment-based universe in the form of DLC or otherwise enabled content), then it would be a nice option for them to log in-world transactions made by Agents logged into their world.
This mechanic would allow entire economic factions and businesses to programmatically manage payments between itself and its users, and provide higher level services in the form of 'expansions', non-downloadable 'DLC', and concisely additional content that could otherwise only be provided freely to the visitor.
Let me know what you guys think and/or if the team already has this in the works, because I (and I'm sure plenty others) would be interested in hearing at least what the API may consist of if implemented as systems such as these can take a generous time investment to get started so any early confirmation would be a bonus!
In any case, keep up the good work at least because the whole Sansar framework's just marvelous!