I was just about to suggest this but you were quicker than me by 2 minutes ;_; here's the proof I've gathered (sorry for the dupe links)

Sellers at 2 keys and below:

http://www.tf2outpost.com/trade/16019696 1 key + 5 ref

http://www.tf2outpost.com/trade/16026114 1 key + 5.33 ref

http://www.tf2outpost.com/trade/15802329

http://www.tf2outpost.com/trade/16000921

http://www.tf2outpost.com/trade/16033471

http://www.tf2outpost.com/trade/16013403

http://www.tf2outpost.com/trade/16034077

http://www.tf2outpost.com/trade/15946921 painted

Unsold at 2.1-2.5 keys:

http://www.tf2outpost.com/trade/15994380 1 day, 2 keys + 2 ref

http://www.tf2outpost.com/trade/16000462 1 day, 2.5 keys

http://www.tf2outpost.com/trade/15976714 2 days, 2.5 keys

http://www.tf2outpost.com/trade/15966345 3 days, 2 keys + 2 ref

http://www.tf2outpost.com/trade/15953898 3 days, 2 keys + 2.33 ref

http://www.tf2outpost.com/trade/15951916 3 days, 2.5 keys

http://www.tf2outpost.com/trade/15967915 3 days, 2.5 keys

http://www.tf2outpost.com/trade/15928260 4 days, 2 keys + 2 ref

http://www.tf2outpost.com/trade/15928000 4 days, 2.5 keys

http://www.tf2outpost.com/trade/15847572 1 week, bp.tf price

Classifieds:

http://puu.sh/5wjwL.png

- 7 sellers at 2 keys, some are painted

- 1 seller at 2.2, 2.25, and 2.3 keys

- 4 sellers at 2.5 keys