I could only find this one and a duped one, which hasn't sold for a while.

Sale 1 {too low, outlier?}:

(See Mini#1)

The Item: http://backpack.tf/item/1251045409

The Trade: http://www.tf2outpost.com/trade/25325483 (5.5 buds B/O)

Seller: http://backpack.tf/profiles/76561198046249467?time=1425961429

Buyer: http://backpack.tf/profiles/76561198067650695?time=1426489200

Sold for a Miami Nights Le Party Phantom + Festive Grenade Launcher +Strange Gold Botkiller Minigun Mk.II + Unique Hat of Cards.

4/16.17 = 0.24 (0.2 keys) 0.2/12 = 0.01 buds

2/16.17 = 0.12 (0.1 keys) 0.1/12 = 0.00 buds lololol

2/12 = 0.16 (0.2 buds)

0.00+0.1+0.2+3 = 3.3 buds

Keys were 16.66-17 (16.17): http://backpack.tf/vote/id/54fa1652b88d8868728b46a5

Buds were 12 keys: http://backpack.tf/vote/id/54dbfe63b98d8841718b4706

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Sale 2:

(See Mini#2)

The Item: http://backpack.tf/item/1251045409

The Trade: http://www.tf2outpost.com/trade/25374471 (5.5 buds B/O)

Seller: http://backpack.tf/profiles/76561198067650695?time=1426585422

Buyer: http://backpack.tf/profiles/76561198119078883?time=1426601118

Sold for these items: http://gyazo.com/8d3ca869d6a189d380fcf97bea1a2faf .

Using backpack.tf recommended prices for painteds etc.

Refined: 7/17.17 = 0.4 keys. 0.4/10 = 0.04

Keys: 4+0.4 = 4.4 keys. 4.4/10 = 0.44 buds

Anger: <was 7.11 ref> 7.11+8.47 = 15.58 ref. 15.58/17.17 = 0.9 keys. 0.9/10 = 0.09 buds.

Fedora: 1.7/10 = 0.17 buds

Force-A-Nature: 1.4/10 = 0.14 buds

Headsplitter: 4.54 buds

(0.14+0.09+0.44+0.04+5.54)*0.9 = 5.62 (Rounded to 5.6 buds)

Has to go down to 5.5 buds because of B/O. Stoopid rules I'll never understand.

Keys were 17.17 ref: http://backpack.tf/vote/id/55059bb6b98d887e448b5239

Buds were 10 keys: http://backpack.tf/vote/id/5506b44dba8d88d4178b472b

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Minis:

#1 - Fruit Shoot: http://backpack.tf/item/2738622419 - Sold for a Searing Plasma Triboniophorus Tyrannus + 7 keys.

2.7*0.9 = 2.43 (Rounded to 2.4 buds)

7/10 = 0.7 buds

= 3 buds total

Buds were 10 keys.

Buyer: http://backpack.tf/profiles/76561198046249467?time=1426040477

Seller: http://backpack.tf/profiles/76561198117073566?time=1426939571

#2 - Headsplitter: http://backpack.tf/item/2612820732 - Sold for a Smoking Hustler's Hallmark + Dead Presidents Das Gutenkutteharen + Strange Specialized Killstreak Festive Knife.

(2.05+1.9+1.1)*0.9 = 4.54 buds

#3 - Knife: Recent sales: $25.26 ($21.96), $30.43 ($26.46), $29.72 ($25.84), $31.99 ($27.81)

Average: $25.51

Keys are ~$2.42 on the market.

10.54 keys.

10.54/10 = 1.05 (Rounded to 1.1 buds)

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As always, please try and keep the comments relevant, please don't make comment comprised only of "upvote" or "downvote". Counter-proof / supportive proof is always appreciated!