Moleskine is basically the Kleenex or Band-Aid of the notebook world; a product so ubiquitous and well established that its brand name becomes a stand-in for the product category as a whole.
So if you like to carry around a notepad and jot down notes or sketches by hand, you should take every opportunity to stock up on Moleskines when you can get them this cheap. $10 is the best price Amazon’s offered on the large black variety in over a year.
If you want more options, Best Buy is running a wide ranging Moleskine sale right now as well, with prices starting at $10.