This was destined to happen eventually

Sale 1

http://www.tf2outpost.com/trade/26725043 Sold with 4 keys of sweets for Twatt Slick Cut

B/O for Slick was 18

Sack had no trade, presuming offered

X + 4 = 13

X = 9

Cut http://backpack.tf/item/2743216145

Sack http://backpack.tf/item/1110701418

Sale 2

http://www.tf2outpost.com/trade/26565381 Sold for DP Pugilist's + 0.5 keys in metal

B/O for Sack was 13

B/O for Pugilist's was 11

X = 11*0.9 + 0.5

X = 10

Pugilist's http://backpack.tf/item/2344403916

Sack http://backpack.tf/item/1110701418

Mini for Pugilist's

Trade listed above http://www.tf2outpost.com/trade/26373119 has a B/O of 11, using 11

Sale 3

http://www.tf2outpost.com/trade/26677986 Sold for a Blank Spec KS Kit

B/O for Sack was 10

B/O for Kit was 11

X = 9.8*0.9

X = 9

Kit http://backpack.tf/item/3907948756

Sack http://backpack.tf/item/1106332333

Mini for Kit

http://steamcommunity.com/market/listings/440/Specialized%20Killstreak%20Kit Sold for $25.28 on 3 August

25.28 + 25.28/1.15 = 47.26

47.26/2 = 23.63

Keys were $2.41 at time of sale

23.63/2.41 = 9.80 keys