What are used SOVTEK 6H30P Tubes worth?

I'm trying to determine what a fair price range might be for used 6H30p Sovteks that test well and are in excellent condition. They have 1000 to 1200 hours on them. Any thoughts?
they sell new for $25-$30 so what ever you can get south of $10 !!!!!
I guess my next question is whether there is a market for them. Do people buy used tubes?
My guess would be you'd have to pretty much give them away. I wouldn't take a chance even at 10 when I could buy brand new with a warranty for 25.

Now....if you offer some sort of warranty that is attractive and can back it up, you might get 15.

Just ask for "best offer" and either accept or decline.
Thanks for the advice guys. These are are matched pairs sold by Conrad- Johnson and, therefore, the reliability is pretty solid. They cost about $35 a piece. I only rotate them out 'cause of my OCD. I have 12 total, six in each foam shipping box. Guess I'll try a no reserve auction, unless someone has a better idea. ;-)