Hey there, this is my first price suggestion (although a re suggestion)! So feel free to leave criticism, support proof, counter proof, or whatever in the comments :P

Also HUGE thanks to Brendan ( http://backpack.tf/u/76561198031371895 ) for all the help!! (and for selling me a cool scattergun :P)

Sale 1: (outlier)

Sold for 11 keys? (B/O of 10 keys, valuing this sale at 10 keys)

http://www.tf2outpost.com/trade/24491386

Sale 2:

Sold for Strange Pan + sweets = (~9.92*0.9) = 8.928 (B/O of 8 keys, valuing this sale at 8 keys)

http://www.tf2outpost.com/trade/24489085

http://i.imgur.com/pd9wvh2.png & http://backpack.tf/calculator/54d2bc19b88d8813508b45ec

Sale 3:

Sold with 7 keys for 1 bud = 7 keys (buds were 14 keys at the time)

http://www.tf2outpost.com/trade/24854919 (said on this trade he bought it without prof killstreak)

http://i.imgur.com/mdXv29a.png (gave me this screenshot for proof)

Support Notes:

http://www.tf2outpost.com/trade/24899704 - B/O of 8 keys (killstreaked)

http://www.tf2outpost.com/trade/24854919 - B/O of 7 keys (killstreaked)

http://www.tf2outpost.com/trade/24491386 - offer of 8 keys

The market for this item without professional killstreak is really bad…

I gathered a lot of invalid proof before I realised killstreaks make the proof invalid :c

These should be all the non-killstreak sales. Well, the ones I could find.

Conclusion:

Sales at 10, 8, 7 keys and an offer of 8 keys ( http://www.tf2outpost.com/trade/24491386 ). There are also B/Os within the 7-8 key range. Due to this, I'm calling Sale 1 an outlier and thus taking the final range as 7-8 keys.

Thanks for checking out my suggestion :D Cya!