Yes, I own one, and in fact, I just bought it yesterday night, so I'm updating the price like any good person would.

I sold my Memory Leak Human Cannonball for the hat and 1 bud. Since it was a trade offer, I'm not applying any overpay. Here is an album of screenshots: http://imgur.com/a/yGOTX

3 buds.

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http://www.tf2outpost.com/trade/20635878 - Swapped 1:1 for a Terror-Watt Towering Titanium Pillar (2.75 * 0.9 = 2.475 rounded to 2.5).

http://www.tf2outpost.com/trade/20635255 - Was also bought for an Aces High Dread Riding Hood (4.1 * 0.9 = 3.69 rounded to 3.7)

http://www.tf2outpost.com/trade/20437361 - Sold for a Disco Beat Down Bone Dome (3.5 * 0.9 = 3.15 rounded to 3.2). He appears to be a PayPal scammer, and I guess that makes the proof invalid, but at least it appears to support the range.

http://www.tf2outpost.com/trade/21253268 - Sold + Disco Beat Down Shooter's Tin Topi (1.5 * 0.9 = 1.35 rounded to 1.4) for a Max's Head. This would put the price of the hat at 1.6, and is likely an outlier with all the sales at 2.5 and above. Plus, the DBD Robo Topi's price could possibly be lower (there's one on the market that's failed to sell at 23 keys for over 3 weeks now).

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There were also a lot of sales for outdated hats that are within the range that can still be used as supporting proof, going off the rules. The Circling Heart Defiant Spartan being one example: http://www.tf2outpost.com/trade/21033740