About 30 states have at least one theater running the films so there’s a good chance that one near you will have the movies.
Even better, tickets to the movies are only $5 a piece, which is one hell of a deal for the XD format which, similar to 3D showings, usually sees a price increase over standard movie tickets.
Not every Cinemark theater will be running the marathon so be sure to check out their site for a complete list of participating theaters.
Tickets appear to be available for individual showings only, not for each marathon, though that’s likely a good deal as several MCU movies will be seen more than once over the course of the week, so you won’t be forced to buy tickets to the same movie twice.