I was bored and looked at the Steam emoticons in the Marketplace. There's 4,017 pages of emoticons (you have to go to page 293 to start seeing ones with inventory actually available for sale). At ten items per page, that means that there's 40,170 different little pictures to decorate your posts with. It also means that there's 40,170 unique emoticon tags. So, much like getting the Gmail address you want, if you're submitting a new cow game to Steam these days, your cow emoticon is probably called :smallcow: or :gamecow: or anything besides :cow: which was already snapped up by Chivalry: Medieval Warfare (and can be yours for 8¢)
The most expensively priced emoticons are a heart and a roll of soiled toilet paper, both priced at $1,885.42 which I'm guessing the is ceiling for pricing stuff in the Marketplace. King Midas at $1,862.14 comes in third because the golden touch is no match for toilet paper. Also, assuming the other two are priced at the cap, that's easy to noodle out. Midas was priced by someone who made an active decision to stay a little below the cap for reasons entirely of their own.
Finally, if you think you'll stumble across something interesting by randomly browsing pages of 3¢ emoticons, you're wrong.
