Yay! first suggestion! 2 pages on Outpost. Needs a drop imo.

Seller at 1 key 14 ref:

http://www.tf2outpost.com/trade/25449180

Sellers for 2 keys:

http://www.tf2outpost.com/trade/25441097

http://www.tf2outpost.com/trade/25450016

http://www.tf2outpost.com/trade/25440298

http://www.tf2outpost.com/trade/25446478

http://www.tf2outpost.com/trade/25447286

http://www.tf2outpost.com/trade/25442852

http://www.tf2outpost.com/trade/25440528

http://www.tf2outpost.com/trade/25372970

http://www.tf2outpost.com/trade/25408075

http://www.tf2outpost.com/trade/25421159

http://www.tf2outpost.com/trade/25386543

Unsolds at 2.5 keys:

http://www.tf2outpost.com/trade/25419632 - 2 days

http://www.tf2outpost.com/trade/25443287 - 16 hrs, very young though

Unsolds at 3 keys:

http://www.tf2outpost.com/trade/25435998 - 1 day

http://www.tf2outpost.com/trade/25439627 - 21 hrs, also young but worth mentioning

http://www.tf2outpost.com/trade/25400864 - 4 days

http://www.tf2outpost.com/trade/25402340 - 4 days

Classifieds at the time of posting: http://backpack.tf/stats/Strange/Wrangler/Tradable/Craftable

4x1.79 key

1x1.84 key

5x2 keys

Rest is asking for offers. As you can see, 2 keys is the most common trading point now. Feel free to point out any mistakes. Thanks!