http://www.tf2outpost.com/trade/20232615 Sold for 50 keys on the 20th of June when earbuds were valued at 16-16.5 keys here. http://backpack.tf/stats/Unique/Earbuds/Tradable/Craftable 50/16.25 is about 3.

Slightly older: http://www.tf2outpost.com/trade/19633120 Sold for these. http://www.tf2outpost.com/trade/20020923

Blizzardy Spartan: http://www.tf2outpost.com/trade/21336976 Pure seems to have been paid (see these keys http://www.tf2outpost.com/trade/21338415 ). http://www.tf2outpost.com/trade/21353682 At most that's 1.5.

These values are from backpack.tf:

Strange Reserve Shooter: 6 refined.

Strange Festive Buff Banner: 4 keys.

Strange Fancy Dress Uniform: 4 keys.

Strange Original: 4.5-5 keys.

The Strange Festive Black Box and the Strange Direct Hit didn't go with that trade.

So the total payment for that Kill-a-Watt Defiant Spartan was, at most, about 1.5 + those items. On the 27th of May, earbuds were 17 keys. Thus the payment was, with 1 key estimating the Strange Reserve Shooter, 1.5 + (1+4+4+5)/17 =(approximately) 1.5 + 0.8 = 2.3. You over-payment people will multiply that 2.3 by 0.9 to get about 2.

Please give comments.