The hardest part about suggestions is sometimes thinking about what is going to be in the italics here

Sale 1

http://www.tf2outpost.com/trade/26898120 Sold for Smoking Gatsby + a bud

Ketche had no trade but clearly was not offered

X = 13.5*0.9 + 3*0.9

X = 15

Gatsby https://backpack.tf/item/996590525

Bud https://backpack.tf/item/93798792

Ketche https://backpack.tf/item/2460471775

Sale 2

http://www.tf2outpost.com/trade/26843585 Sold for Pro KS S. Rocket + 4 keys in sweets

X = 10.7*0.9 + 4*0.9

X = 13

Rocket https://backpack.tf/item/1799170384

Ketche https://backpack.tf/item/2460471775

Mini for Rocket

http://steamcommunity.com/market/listings/440/Strange%20Professional%20Killstreak%20Rocket%20Launcher Sales of: (27.82 + 29.27 + 24.32 + 26.99 + 32.32)/5 = $28.14 on average on September 26

28.14 + 28.14/1.15 = 52.61

52.61/2 = 26.31

Keys were $2.45 at time of sale

26.31/2.45 = 10.7 keys

Sale 3

http://www.tf2outpost.com/trade/26865046 Sold for Flies Fukaamigasa

B/o for Fukaa was 18

Ketche had no trade, presuming offered

Was being brokered by "candy is mine" most likely

X = 16

Fukaa https://backpack.tf/item/471606876

Ketche https://backpack.tf/item/4011509308

Mini for Fukaa

https://backpack.tf/vote/id/5615fad9b98d885e54cc1b24 15.5 keys, using 15.5

Seller

http://www.tf2outpost.com/trade/27121824 14 keys