Gonna stick with unusual suggestions.

Sale 1

Sold for 10 keys

http://backpack.tf/profiles/76561198018528305#!/compare/1473638400/1473724800

http://www.tf2outpost.com/trade/28446990 ----- B/O was 11 keys, took 3 weeks.

=======> 10 keys

======================================================

Sale 2

Quicksold with ~1 key in sweets for 10 keys

http://backpack.tf/profiles/76561198145249652#!/compare/1473724800/1473811200

http://www.tf2outpost.com/trade/28485969 ----- B/O was 11 keys, sold quickly.

=======> 10 - 1 = 9 keys (qs)

======================================================

Sale 3

Probably SCM

http://backpack.tf/profiles/76561198150845873#!/compare/1471046400/1472083200

http://backpack.tf/profiles/76561198018528305#!/compare/1471046400/1471132800

No Outpost trade.

=======> Not using

======================================================

Sale 4

Probably SCM again

http://backpack.tf/profiles/76561198225384128#!/compare/1468800000/1473724800

http://backpack.tf/profiles/76561198150845873#!/compare/1470873600/1471046400

No Outpost trade

=======> Not using

======================================================

Sale 5

Bulk for Planets Pyromancer's Mask

http://backpack.tf/profiles/76561198084774041#!/compare/1473379200/1473465600

No Outpost trade

=======> Not using

======================================================

Sellers

- http://www.tf2outpost.com/trade/28490890 ----- 10 keys for 3 days

- http://www.tf2outpost.com/trade/28488121 ----- 11 keys for 5 days.

- http://imgur.com/a/hMScg ----- 11 keys for 9 days

Summary

- Sales for 9 (qs) and 10.

- Sellers for 10 and 11.

Going with 10 keys. Criticism appreciated!