Merchandise sales - Where does the money go?

[MattRVA]

Let’s say I buy a $30 t-shirt at a show. How is that money split amongst the shirt designer, show’s producers, etc? This may seem like a trivial question to some - or a simple question to those in the industry - but as a fairly regular theatre goer I’m curious about how the business aspect of things like this works. How much of merchandise sales go toward supporting the show, so to speak?