Story I got is that somebody special ordered the Blue Ring then changed their mind
Somebody I know has a mimic octopus, which is the only day hunting octopus (or one of very few). However, they are extremely expensive (usually in the $300-400 range) but really cool looking with black & white stripes. Other octopus usually only come out at night & hide most of the time so you'll rarely see your pet. You also need to set up a special octo-escape-proof tank system. Unfortunately, most cephalopods are very short lived so you can only enjoy them for a few short months or a couple years at most.
Like with seahorses, anybody interested in getting an octopus needs to do lots of research & set up a species tank to be able to take care of their purchase necessary. Definitely not suitable for an impulse buy.
Anthony