Moooooo..... Loads of these on Outpost for 2.5 Keys, usually 2 Keys + 2 Ref WHich is below 2.5 Keys. Proof below.

http://backpack.tf/classifieds/search/robro - 3 at 2 keys (1 has purple paint)

http://www.tf2outpost.com/trade/10147445 - 2 keys 2 ref - 2 days

http://www.tf2outpost.com/trade/10136353 - 2.5 Keys -3 days

http://www.tf2outpost.com/trade/10182231 - 2 keys + 1.33

http://www.tf2outpost.com/trade/10165030 - 2 keys + 1.66 ref

http://www.tf2outpost.com/trade/10209754 - 2-2.5 keys (so obviously everyone will pay 2 keys for it instead of 2.5)

http://www.tf2outpost.com/trade/10171975 - 2 keys + 1 ref (seems to have an add, but not sold yet)

http://www.tf2outpost.com/trade/10164565 - 2 keys

http://www.tf2outpost.com/trade/10164565 - 2 keys

Happy Trading!