Branding irons and barbed wire are really big collector items in some areas in the West.  My wifes uncle has been a surveyor out of Lovington,NM since he got home from WWII and has run across a lot of old barbed wire.  He gave me some examples, but he didn't know that it had to be of a certain length to be collectable (16 or 18" I forget which) .  Still, they're interesting, and I have them tacked up in my shop.