I was browsing some of my purchases from the mint, some of which I totally forgot I had bought

Anyways I decided to check
ebay to see what some of them are going for and came across this:
http://www.ebay.com/itm/2014-CANADA...182202799616Is this a common practice? The coin was originally sold at $99 from the mint. Also the person claims, and I quote: "THE POPULATION FOR THIS COIN WITH THE BROWN LABEL AT PF 70 ULTRA CAMEO IS ONLY 4 COINS ACCORDING TO THE NGC" Wouldn't most, if not all, coins be the practically the same?