You may want to query on the Custom Price amount that they have assigned individually to an event in a Program query, that is different than the default price types in the Program.
This is not a field that we can query on in a Program query. We do have an idea in our Altru community idea located here. We encourage you to vote on this post as this is an opportunity to have a voice in the product development process. Our Product Management team uses a variety of methods to determine new features in Altru, and the ideas in the Community is one way they do this, so your vote helps Product Management prioritize the new features that we put into the product.
Additionally, if tickets have been sold to that event, the Sales Order Item\Sales Order Item Ticket\Tickets\Price to see the price paid for the event ticket.