All potatoes are not created equal

It's been a quiet week. There's been no clowns to offend me and my epic war with a particularly aggressive moth is hardly worth writing about. Then again neither is this:

When is a potato not a potato? or more accurately why are some potatoes worth more than others. I don't know but here's the proof.

There it is, clear as day, in price per kg different potatoes are worth different amounts. SHOCKING! Stop this injustice now... or something.
cheers,
R.