Updating the lower range in the lower-tier hats.

http://www.tf2outpost.com/trade/9705504 Buying any unusual for 12 keys. (Feel free to post if you find more trades buying @12 or more)

http://www.tf2outpost.com/trade/10816039

Offers:

Planets Geezer (13 keys) and "some keys", he had 3 keys to add. I'll consider this around 15 keys

12 keys

12 keys + 2.33

http://www.tf2outpost.com/trade/10816039 Offers:

13 keys

Low end obvious, high end between the highest pure offer and the highest unusual offer.