Growing up we had a few axes that where very very old and they where very well made durable axes. My father still has them to this day ! That said technology has really moved forward and if you spend on a current axe they are hardened alloys that are much tuffer than older axes. Most people buy older axes for nostalgic reasons at least the collectors I know. There is really nothing cooler than to split with a hand made axe from the 1800's after all.
Pete
I have a Collins Legitimus Axe that belonged to my grandfather and his brothers when they were kids. I use it from time to time and it is a fine piece, but since it still has a 70 year old handle on it with nice petina, and I don't want to put a new handle on it, I don't give it the exercise it deserves and mostly keep it on the wall in my bar as decoration. I also have a nice Warren Tool Co axe from him made here in Pa that gets the same treatment.
As BigRedd mentioned, ebay isn't a bad spot too look, although the prices for many seem to be high the last few months for some reason.
The flea market suggestion (or garage sales around here) is a good one as well but that won't help unless you are patient and persistent.
pen