Thanks to Jacobmeister for the help :)

Sale 1:

Sold with a Smoking Prancer's Pride for a Frostbite Swagman's Swatter

(82*0.9) - 13 = 60.8 rounding to 61 keys capping at 60 keys

http://www.tf2outpost.com/trade/25946449

http://backpack.tf/profiles/76561198078648512?time=1431586800 (May 14th)

http://backpack.tf/profiles/76561198078648512?time=1431673200 (May 15th)

Sale 2: (outlier)

1:1 with a Blizz. Gym rat

15 keys or something, definitely an outlier :P

http://backpack.tf/profiles/76561198169817323?time=1428476400 (April 8th)

http://backpack.tf/profiles/76561198169817323?time=1428822000 (April 12th)

Sale 3:

http://backpack.tf/profiles/76561198008608496?time=1431241200

B/O of 40 for 2 weeks, it is impossible to tell what sold for what, but with a B/O of 40 for 2 weeks it should be included in this range that probably won’t change again for a while.

Notes:

Mini for the Frostbite Swagman's Swatter:

http://backpack.tf/vote/id/555d6ad5ba8d88923a8b45ee

Mini for the Smoking Prancer's Pride:

1:1 with a Blizz. Ketche

13 keys

http://backpack.tf/profiles/76561198155507251?time=1431068400 (May 8th)

http://backpack.tf/profiles/76561198155507251?time=1431241200 (May 10th)

Conclusion:

This has apparently been sold to an anti-freeze collecter, taking the final range at 40 - 60 keys.