Counter. Also maxed out at 50 suggestions!

Other suggestion is using invalid sales.

Thanks to Blaze for supplying sale #2 and #3 <3

Sale #1:

Sold for a Memory Tam + 4 keys + Black Bills (3) + ~28 keys other items

22 + 28 * 0.9 + 4 + 3 = 52 keys

Low outlier, not including.

http://backpack.tf/profiles/76561198174932770?time=1426417086

http://backpack.tf/profiles/76561198174932770?time=1426575600

Sale #2:

Sold 1:1 for a Miami TC (75)

Valuing at 75 keys

Offered on the TC, no overpay.

http://www.tf2outpost.com/trade/25942442

Sale #3:

Sold 1:1 for a Vivid Lucky Shot (76)

76 * 0.9 = 68.4 keys rounding to 68 keys

http://www.tf2outpost.com/trade/25869154