First time doing this with multiple sales, feel free to correct me at any juncture. Resuggesting as recommended because the mini was in pure.

Sole Mate is my favourite hat so I've always wanted to set myself the challenge of pricing an Unusual one. Here we go.

Sale 1:

Sold for a duped Cloud 9 Toy Soldier

Toy Soldier: http://backpack.tf/item/2368572735

Sole Mate: http://backpack.tf/item/3374210436

Backpack of buyer before: http://backpack.tf/profiles/76561198015382027?time=1424505600

Backpack of buyer after: http://backpack.tf/profiles/76561198015382027?time=1424678400

Mini at 1 bud 6 keys = 1.5 buds (mini is in pure)

Sale 2:

Sold for Specialized Killstreak Australium FaN, 2 keys and Conga

Backpack of seller before: http://backpack.tf/profiles/76561198081172172?time=1422172800

Backpack of seller after: http://backpack.tf/profiles/76561198081172172?time=1422259200

http://steamcommunity.com/market/listings/440/Strange%20Specialized%20Killstreak%20Australium%20Force-A-Nature

Spec Aussie FaN sales from 25th-27th January were £31.20, £30.52, £30.41, £29.05, £28.82 and £28.83, average of £29.81 ~$46.18. Converted to 19.57 keys

20.57*0.9 + 2 = 20.5 keys. Buds were 13 keys on the 26th so ~1.6 buds

Sale 3:

Sold for 1 bud, 7 keys

Backpack didn't record the bud, so I decided to check some histories.

History of Sole Mate: http://backpack.tf/item/3402299718

History of bud: http://backpack.tf/item/218576510

History of keys:

http://backpack.tf/item/2760396558

http://backpack.tf/item/2912698923

http://backpack.tf/item/1732035396

http://backpack.tf/item/3341934750

http://backpack.tf/item/2967715345

http://backpack.tf/item/2798688954

http://backpack.tf/item/3430669673

Buds were 13 keys so ~1.5 buds

Sale 4:

Possibly sold on the market?

Backpack of seller before: http://backpack.tf/profiles/76561198079750837?time=1421913600

Backpack of seller after: http://backpack.tf/profiles/76561198079750837?time=1422259200

Nothing in the seller's backpack to suggest it sold for items.

Mini:

Duped Toy Soldier - sold for 1 bud 6 keys: http://www.tf2outpost.com/trade/24979063

All feedback is welcome and appreciated. At the risk of sounding incredibly annoying, please don't be too aggressive with your criticism. Thanks folks!