2D Boy, the independent game studio behind World of Goo, recently celebrated the game's one-year anniversary by offering it at whatever price buyers cared to pay. They've now released some sales statistics about how people responded to the opportunity. The average price during the sale was $2.03; the game normally retails for $20. According to a survey of why people paid what they did, 22.4% said it was all they could afford at the time, and 12.4% said they already owned World of Goo and were buying it for a different platform. (Yes, there is a Linux version.) Over 57,000 people took advantage of the offer, which was enough for 2D Boy to term it "a huge success." Interestingly, they also saw a significant increase in sales through Steam, and a smaller increase through Wiiware. They've decided to extend the experiment until October 25th.