Is it free?
Short answer
Nothing has been decided, because deciding pricing for a product with no users is a way of avoiding harder questions. If it launches, joining as either side will be free at the start.
The longer version
The waitlist costs nothing and always will — there is nothing to charge for yet, and charging for a place in a queue would be a strange way to find out whether the queue should exist.
If it launches, joining as either side will be free at the start. Charging before there is proven value on both sides would suppress exactly the signups needed to make it work, and any pricing decision made now would be a guess dressed up as a plan.
The likeliest shape, if it gets that far, is that the introductions stay free and something around them is paid. But that is a guess too, and it will be made with data rather than in advance.
The full argument, with the rest of the picture around it:
What Push & Pitch Is, And Why It Might Not Exist