I've always had a facination with octopi, but only recently have considered keeping one as a pet. I've checked out the forums and it seems like there is alot of stuff required to properly keep one. My question to those who have these amazing creatures as pets is, how much does it cost (on average) to set up a tank and later to maintain the tank/octopus?

A good rule of thumb is about 15$ per gallon to setup...this includes live rock, filters, etc...there are always ways to cut costs, but this will at least give you and idea...
greg