Simply so, how much is an antique tea cart worth?

Antiques & Collectibles: Tea carts are linked to centuries of tradition. Recent sale prices for mid-20th century tea carts range from $50 to $130, based on condition.

Subsequently, question is, is Kling furniture valuable? At this time, the simple fact that a piece of furniture is identified as Kling does not automatically make it valuable--it is akin to asking if a 1965 Ford car is valuable.

In respect to this, what is a tea wagon?

tea wagon (plural tea wagons) (US) A table on wheels used to take food or drinks from the kitchen to the dining-room. (US, film, slang) An audio mixing console on wheels.