I havent made a suggestion in a long time so I greatly accept any counter-proof / proof or maybe stuff I should do different.

http://www.tf2outpost.com/trade/19485013 Sale 1! (1 Month old) Offered on a eerie berliner, added ~ 5 keys in items. (Overpay not calculated since he offered) 2.9 + 0.3 = 3.2

http://www.tf2outpost.com/trade/19510532 Sale 2! (Also 1 month old) 1:1 With C9 Private Eye http://www.tf2outpost.com/item/440,2571346299,388,5 3,3 x 0,9 = 3.

http://www.tf2outpost.com/trade/19318959 Sale 3! (Another 1 month old) 1:1 Terror-Watt Lucky Shot, 3,2 x 0,9 = 2,9

http://www.tf2outpost.com/trade/18842970 (2 Months old) Sold for Metal Gear Rising: Revengeance, 14 Keys - Outlier

http://www.tf2outpost.com/trade/18858828 B/O of 50 keys pure / 3 buds when valued at 16.5.

I know that most of these are a little old, but I couldnt find any recent sales. 2.9 in low end and 3.2 in high end seems fair from the sales and buyouts.