I would assume the same price as the previous entries but idk. Amazon is listing it at $26.99, but that may be some sort of pre-order special. A full-price new version of the Tyrael one runs $29.95.
Also, just spitballing here, but I doubt they'll be in the Gear Store or they'd be open to virtual attendees which could conflict with a publishing/release agreement? It might be its own separate thing at the con. (Again, just putting that out there, I have no idea.)