I'm sure you guys are all familiar with the Steam trading cards, right? You play a game and randomly receive a handful of trading cards for that game, and if you collect them all you get a shiny badge. You can get the same badge multiple times to increase it's "level."
With the Steam summer sale, you get a special summer sale card for every $10 you spend. Alternately, you can buy them for about $0.20 on the marketplace, or trade with friends to get the cards you don't have. If you collect ten separate cards, you can get a spiffy summer sale badge.
Well, this crazy bastard with the Steam name of PalmDesert has a level 2500 summer sale badge, meaning he collected
25,000 cards. Assuming he bought the vast, vast majority of them on the marketplace at $0.20 each, he has spent a whopping $5,000 for the honor.
http://steamcommunity.com/id/palmdesert/gamecards/303700-b0b
(...and you guys thought I needed a 12-step program for Steam.)