Hard to work with item histories right now. :D Hopefully I've found everything alright.

Sale #1:

Sold for 204 keys + Bubbling Pro Ushanka (30 pure) + Nuts Stash (30) + Pro Australium Stickybomb (~24)

http://www.tf2outpost.com/trade/27682483

The Nuts Stash and Ushanka were sold for 30 pure each, so I'll be valuing them at that. The Ushanka did quicksell, but it does not matter because the sale is capped.

Ushanka mini: http://i.imgur.com/4xe48Ge.png 30 pure

204 + 30 + 30 + 24 = 288 keys

B/O was 280 keys. This sale happened within hours of being posted.

Sale #2:

http://www.tf2outpost.com/trade/27744042 Quick-sold for a value around 240 keys. This should be better treated as an outlier for now, most of the sellers seem to be rejecting offers around this value.

Sale #3:

This sale is too old to use, but it supports the first sale:

http://www.tf2outpost.com/trade/27258759 Sold for ~295 keys according to Woifi in the previous suggestion

Offers:

• http://www.tf2outpost.com/trade/27530074#p64471282 Duped PE Blighted Beak (~120) + Pro KS Aus RL (70) + Pro KS Aus Sticky (21) + 69 keys

  This should be close to 280 keys, though the seller did not accept. Beak is valued approximately.

• http://www.tf2outpost.com/trade/27530074#p64435051 MG Cone. Last suggested with a sale at 250 pure.
• http://www.tf2outpost.com/trade/27550121#p64433355 Declined 200 keys, says they've been offered 220 as well but there is no evidence for it
• http://www.tf2outpost.com/trade/27709068#p64554617 Declined 220 keys

Forgot to include this.

Here's the screenshot of the first sale:

http://i.imgur.com/Gtg6FoS.png