Was he talking about eating one? Im confused...but if he was, 5 bucks a POUND!? Wow...thats a lot compared to the Octopuses in my local fish market...here they only cost like 3 bucks a peice and they aren't small. I hate seeing them dead though, or battered and torn apart...cuz there such amazing animals.
At tropical fish shops in my neck of the woods (Los Angeles - San Fernando Valley), I've seen the prices on octopus range from about $29.00 - $69.00. Most have been either pygmies (sold as "baby" octos) or have been our local "mudflat" octopus - the same variety found in the seafood section at Ralph's supermarket.
The staff generally know nothing about their charges, if they are a more exotic variety aren't sure how old they are, etc. When the time comes for a ceph, I'm sticking with people/companies that breed their own so I know the history and health of the individual animal.