The last suggestion on this hat has no proof and only 12 votes, looking to make it a little more accurate.

First suggestion, sorry if the proof isn't good, the hat is fairly low volume for some reason.

http://www.tf2outpost.com/trade/10708529

10 Keys + Pink Bills (8 keys 2 ref) + Silver Flamethrower (1 ref) + S. Rocket (1 ref) + S. Sticky (.33) + Medic Mountain Cap (lvl 99) (1.33) + Battery Bondlier (1.33) + Tam O' Shanter (1.33)(lvl 100)

Total: 18 Keys + 8.33 or 19 keys + 3.33

http://www.tf2outpost.com/trade/10786783

This is the last trade he had up so I decided to add him and ask. Here is the full chat log, I had no prior contact with him and he did not know I own a Planets Shanter.

http://imgur.com/SNem7G0

He says he sold it for 1 bud (22 keys at time of trade), he sold it in bulk (as the log says), and I cant see a reason for him to lie. He bought it for 19 Keys.

http://i.imgur.com/iAdW5NZ.png (you can see my terrible quick typing here, it was getting late)

This is the chat log of the discussion I had the guy that sold it to that that1kid, just trying to confirm the 19 key price point. Again I had no contact with him beforehand, and he did not know I own a Planet O' Shanter.

http://i.imgur.com/9cPqJAE.png

Chat I had with another guy who sold his for 17 keys + some discussion about pricing.

Thanks!

Full Disclosure, Bought mine for 19 + Sweets