This hat is in desperate need of a bump. Unusual offers if there are any are accounted for by mid range x .9 and any offer that is less than 3 months old are being accounted for, since the last suggestion was then.

Only one for sale on Outpost, and the trade is 6 months old so it's likely that a sold trade can't be used:

http://www.tf2outpost.com/trade/7540416 - Offered a TS Summer Hat (13.5 keys), 20 keys (possible outlier), 13 keys, 5 keys + 51 ref (around 14 keys), 14 keys + F. Medi Gun + 6 refined (around ~16 keys), 9 keys + TS AC (whatever that is), 13 keys, 14 keys, and 15 keys.

Conclusion: This hat is rarely traded, but it does indeed need a bump as offers have shown that the current range is very outdated. I made the range 14-15 keys since most offers tend to fall within that range. If you think the range is messed up, please state why. Please provide counterproof if you find any. Thanks for your time.