It seems as if I have seen them posted fairly regularly on Ebay for the rebuilds often less than $700.00 I also noticed used rebuildable for $200-$400 sold on ebay. In my mind any specific large ceramic transmitting tube with such capabilities as the 3cx3000a7 certainly seems reasonably bargain priced at anything under $1000.... I think if a person was resourceful enough and took his time, he could probably eventually score a decent tube with plenty of life for $400.... I knew of a 3cx15000 that was sealed in the original box that sold at an estate sale for only a couple hundred bucks. If I knew they were going to do that I would have bought it.