Price could use a bump, considering people are willing to pay a bit for these.

Sellers

http://www.tf2outpost.com/trade/8334567

-10 key offer

http://www.tf2outpost.com/trade/6755016

-Bill's Hat + 4 keys ~ 12 keys ({G$CD}Cobalt's offer)

http://www.tf2outpost.com/trade/8546816

-9-10 key offer (declined)

http://www.tf2outpost.com/trade/8342647

-11 key offer

http://www.tf2outpost.com/trade/6026098

-8 key offer

-TS Bill's offer

http://www.tf2outpost.com/trade/7567966

-10 Keys offer

-TS Bill's Offer

http://www.tf2outpost.com/trade/7380307

-11 key offer (old/2 weeks)

-Bill's + Kringle Collection ~ 10 keys

http://www.tf2outpost.com/trade/8158633

-9 key offer

http://www.tf2outpost.com/trade/7358000

-10 key offer

Buyers

http://www.tf2outpost.com/trade/8367184

-Buying for 8 keys

A lot of buyers are trying to pay 7 keys, but little to no success. People will pay more than 7 keys, and offers that go above 9 keys are usually a bit older or are in items, so I didn't change the high end just yet.