I gave about $4,000 USD for a 4 Inch 4-Way valve in grey iron around 2014. It had about a 3 week lead time.

Ours was a high temperature 100 psi application in a blower regenerated desiccant air dryer. It used 2 x 2400 lb desiccant tanks one drying compressed air and the offline tank regenerating by heating to 350 F with forced air flow and a 45 KW heater. It dried 1,000 cfm @ 100 psi to a -40 F dew point. If you blew the air on your skin you could feel the air suck the moisture out of your skin.