Re-suggesting, 3-3.1 is a quicksell.

bud = 19 keys

3 buds = 57 keys

3.3 buds = ~62-63 keys

Not incluiding any level 1/7 nor gifted, unless sold above current range

Quicksold below 3.2

http://www.tf2outpost.com/trade/21911057 - 3 (black)

http://www.tf2outpost.com/trade/21886536 - 3.1 (black)

http://www.tf2outpost.com/trade/21915968 - 3.1

Sold

http://www.tf2outpost.com/trade/21882385 - 3.2

http://www.tf2outpost.com/trade/21920415 - 3.2

http://www.tf2outpost.com/trade/21910510 - 3.2 (pink)

http://www.tf2outpost.com/trade/21908987 - 3.2 (TS)

http://www.tf2outpost.com/trade/21886165 - 3.2 (lime, sold 2)

http://www.tf2outpost.com/trade/21874627 - 3.2 (pink, sold 2. also sold a gold one)

http://www.tf2outpost.com/trade/21875894 - 3.3

http://www.tf2outpost.com/trade/21795820 - 3.3

http://www.tf2outpost.com/trade/21797331 - 3.3 (lime)

http://www.tf2outpost.com/trade/21875016 - 3.3 (sold 2)

http://www.tf2outpost.com/trade/21842761 - 3.3

http://www.tf2outpost.com/trade/21585258 - 3.3

http://backpack.tf/classifieds/?item=Max%27s%20Severed%20Head&quality=6&tradable=1&craftable=1

First few non-level-1 clean ones are listed at 3.2, rest are most commonly found at 3.3+