Sale 1: 13 keys pure but quicksell so not useable (thanks to xth3rm4lx & Alberny for pointing this out)

http://backpack.tf/profiles/76561197962570725#!/compare/1492214400/1492300800

Sale 2 (dupe): Sold for buds (1.8 keys) + Circling Peace Sign Hotrod (15.5 keys; in-date) --> 17.3

http://backpack.tf/profiles/76561198257090946#!/compare/1492560000/1492646400

Buyout was 16 http://www.tf2outpost.com/trade/28865786 (credits to Alberny for finding this) --> 16 keys

Sale 3 (dupe) Sold together with 2 keys for Kill-a-Watt Barnstormer (17.5) --> 15.5; rounding to 16 keys.

http://backpack.tf/profiles/76561198021055079#!/compare/1491004800/1491091200

http://backpack.tf/profiles/76561198256589823#!/compare/1491004800/1491091200

Sale 4 (dupe): Sold for ??? Keys; not useable unless someone goes through all these keys but most likely in the suggested range.

http://backpack.tf/profiles/76561198159855421#!/compare/1492732800/1492819200

Has been unsold at 15 keys for 12 days but 2 sales at 16 keys.

http://i.imgur.com/cEgVG2n.png

--> Suggesting range from 15-16 keys