Apparently growing wasabi is rather expensive and difficult to do in most parts of the world. Even in Japan it looks like it is quite a hassle.
Finding fresh wasabi like this is pretty uncommon in most stores, but if you root around (pun intended), you can find it at some shops. These pictures were taken in Nagano last weekend. It looks like this vendor was selling quite a selection of different sizes. Ranging from small (300 yen for two) up to 2,500 yen for the largest.
I’m not quite sure of the type of wasabi, looks like there are about 18 different types of wasabi here in Japan, and I didn’t get a close enough look at the leaves to make a distinction!
I thought of buying some, but was kind of in a hurry… maybe next time!