The listing, Steam Badge - Left 4 Dead 2 has ended.
You can craft the badge even if you don't own the game .
You will receive a complete set of cards for Left 4 Dead 2 , 8 Steam Trading Cards .
When you craft the badge you will receive also 100XP , a random emoticon and a random profile background item .
The winner must become friend with me on steam .
I will send the cards on a trade or on a trade offer .
More information here : http://steamcommunity.com/tradingcards/faq
What is a badge?
A badge is an icon on your profile (and tied to your account) that represents the trading card sets you've collected or your participation in an event.
What do I get when I craft a badge from my Trading Cards?
In addition to getting the Game Badge itself, you'll get:
A random emoticon item created for this game, that can use in chat or discussions;
A random profile background item created for this game, that can use on your Steam Community profile
A chance to get a discount coupon for a different game or DLC
100XP, which may increase your Steam Level
If your Steam Level increases, the limit on the size of your friends list will be increased by five, and potentially you'll unlock the ability to customize your profile with showcases
How do I craft a badge?
From your Profile page, click on the "Badges" link near the top of the right column or select "Badges" from your persona name drop down in the Steam menu. From your Badges page, the "Badges in Progress" tab will show which badges are ready to be crafted. Select a ready to craft badge to view its details and click on the blue "Craft a Badge" button.