Ebay's values are completely random and subject to the whims of the various bidders, phase of the moon, whatever. I have seen some truly insane bidding wars. An ad-hoc pump for 350$? The week before a complete vintage PX10 with a nearly mint ad-hoc sold for 435$ (?). I know the pump on the PX was mint because I bought the bike. Makes no sense.

Last Gran Jubilee I bought was 15$ (late 70's, I think). Most of it is still in the basement.

I'm for higher prices when I sell and lower ones when I buy.