Counter.

Sale 1:

Sold for a Burning Das Guten + 15 keys = ~81 keys with overpay

http://backpack.tf/profiles/76561198042187189?time=1425884400 (March 9th)

http://backpack.tf/profiles/76561198042187189?time=1428562800 (April 9th)

http://gyazo.com/677b359c5092792fc79bc45042dbe375

Mini on the Guten:

Sold for 6 buds + 11 keys = 73 keys

http://i.imgur.com/Gn1AX4u.jpg

Sale 3:

Sold for a Stormy Yellow Belt + Something Burning Baker Boy + S. Pro KS Loose Cannon = ~70 keys with overpay

http://imgur.com/sBLpr5T

http://imgur.com/o0SWsd6

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

Minis:

Yellow Belt - 30 keys http://imgur.com/kDBji6b

Baker Boy - 42 keys: http://imgur.com/b1ssYAf

Loose Cannon - ~6 keys: http://imgur.com/P45bb9C

Sale 3: (Duped)

Sold for 8 buds = 64 keys

http://backpack.tf/profiles/76561198076933926?time=1426575600 (March 17th)

http://backpack.tf/profiles/76561198076933926?time=1428217200 (April 5th)

Not counting the duped sale in the range, rounding to 70-80