Counter Suggestion, borrowing some proof from the other suggestion.

http://www.tf2outpost.com/trade/19527774

Was bought by blue for 6 buds and 9 keys = 6.5

Confirmed by blue

http://imgur.com/joG2JoC

http://puu.sh/9By11/97aebcfb72.png

I bought one today for 117 keys = 7.3

Credit to alaska:

Sold for hearts swag+ghost drills.

http://puu.sh/9dZpW/ab4da3c26d.png

4.6(see mini below) + 2.9(see mini below) 2.9+4.6=7.5

Mini for drills

Trade: http://www.tf2outpost.com/trade/20027656

Sold for logo tossle (~2.7) = 2.4(overpay calculated) + 1 bud mixed = 3.4

Checked with seller: http://imgur.com/evmkBGm

Trade: http://www.tf2outpost.com/trade/20144543 Sold for 3 buds pure

http://i.imgur.com/75RvTsY.png

http://i.imgur.com/un7gf6a.png

3.4+3=6.4\2 = 3.2 x .9 = ~2.9

Mini for Swag

Trade: http://www.tf2outpost.com/trade/18834135

Sold for 5 pure

Proof: http://tinypic.com/view.php?pic=2i8az9v&s=8#.U54mUS_HLC1

http://www.tf2outpost.com/trade/17859719 sold for 5.2-5.3 in all keys confirmed by seller

http://imgur.com/3zZJTj2

Backpack confirms contents

http://imgur.com/jpffakJ

http://www.tf2outpost.com/backpack/139336

5.2+5=10.2\2=5.1 x .9 = ~4.6

http://www.tf2outpost.com/trade/20362007

Sold for 4pure + clean c9 tyrants(5.2)=~4.7 overpay + Smoking lucky shot (1.5) = ~1.3 overpay

4+4.7+1.3 = 10

http://www.tf2outpost.com/backpack/266965 <---Backpack confirms items

Confirmed by Blue http://imgur.com/06U36Bs

Four sales: 6.5, 7.3, 7.5, 10

Looking at the offers and sales on the Rack it looks like 10 is an outlier and 6.5-7.5 makes a better range, especially considering 6.5 and 7.3 were both in pure.

Feel free to comment and share your opinions.