Overpriced Tube Amps

I love tube amps, Ive owned many solid state the great ones, Blah Blah Blah. Ive been watching the prices increase on these old designs now 20 year old units going for 50% of original cost rusty old xformers and all. Dont be stupid when purchsing these things. Id love to name brands but i wont. Another thing is the prices some people charge for tubes 100 each? These things cost $3.00 new. I know they can make or break that 4500.00 tube amps sound but come on.
I have a 30,000 system and have yet to spend more then 15.00 each. I dont get it.