This needs a small bump, been 4 months.

Anyways, go into the topic. I'd say this should worth around 3 to 4 keys, or even 6 keys due to it's rarity(Only 94 in the game!).

A guy is selling it on the Classified of backpack for 6 keys: http://backpack.tf/u/76561198064273568

Now, before you go and say that it is a specialized killstreak & worths more - The specialized killstreak worths 5 refined - 2 keys, as that's how much people sell the strange one for, since the kits wouldn't really make such difference.( http://www.trade.tf/classifieds/search/Sell/All/Mantreads/all/Specialized%20Killstreak/1 )

So even if it has the KS applied to, it still worths 4 keys.

Also, a clean Collector's Mantreads was quickly sold at 3 keys(Yes I bought it, since it did indeed worth more than 2 keys.): http://www.tf2outpost.com/trade/23264857

Also it is hard to find people who sell this in-game without KS applied to[IF you find one].

Only low amount of those people that have the Mantreads neither sell it w/ some keys for an unusual(E.G http://www.tf2outpost.com/trade/23256275 ), or sell them as a part of a set(E.G http://www.tf2outpost.com/trade/22260010 ) so good luck.

Also, so far I didn't see any quick sells of it less than 2 keys, so what do you think?.