Just for a price comparison, I got my Working 19" K7602 CGA Wells Gardner monitor last week for 125$. It does have a tiny bit of burn in with a KO in the top middle, possibly from a fighting game. But with the smoked glass in front of it you simply cant see it.
And when games are running, the burn in dissapears.
Also was free shipping since I picked it up like less than 3 miles away from my house.
If anyone lives in the San Diego area, I can give you some information on a few places to purchase used monitors, and or full working cabinets. Very cheap prices I might add.