Quite the rare item, so proof is hard to come by, found what I can.

Also, I apologise if this goes badly, but it's the first i've done in a while.

Sold:

http://www.tf2outpost.com/trade/22013591 Several trade offers of 4 keys, sold for the last one at 4.

http://i.imgur.com/6TwlSnj.png Sold for 8 ToDs for the strangifier itself (Around 4 keys taking into account it's the strangifier)

http://imgur.com/SOGI9Ex,t893hkm,9psP5dE - Some Screenshots of 4 key offers, plus a offer of a collectors Quick Fix (5 keys at time)

http://www.tf2outpost.com/trade/22406383 - QS at 2 keys, sold already.

Steam Community Market also supports this price, at 8$

Sellers:

I realise these aren't too relevant, but it's hard to find past sales.

http://backpack.tf/classifieds/?item=Fashionable%20Megalomaniac&quality=11&tradable=1&craftable=1

One on Classifieds at 4 keys

http://www.tf2outpost.com/trade/21126154

Several offers of keys, one recent at 3 keys, which was declined. Also had previous offers of 4 keys.

Thanks!

If you have any suggestions, proof or counter proof, please let me know.