Classifieds: http://backpack.tf/classifieds?item=mann+co.+stockpile+crate+key

Most sellers are 1.1-1.2

Take note that the prices are rounded in keys so for example 1 key + 2 ref is 1.23, rounded to 1.2. 1 key, 1 ref is 1.16, rounded to 1.1.

Sellers:

http://www.tf2outpost.com/trade/20510223 - 8 ref in items (~0.88)

http://www.tf2outpost.com/trade/20519815 - 8.33 ref (1), sold

http://www.tf2outpost.com/trade/20480139 - 9 ref (1), sold

http://www.tf2outpost.com/trade/20504634 - 9.33 ref (1)

http://www.tf2outpost.com/trade/20488113 - normal key + 1 ref (1.1), many adds

http://www.tf2outpost.com/trade/20474371 - normal key + 1 ref (1.1), 1 sold

http://www.tf2outpost.com/trade/20429709 - normal key + 1 ref (1.1), sold

http://www.tf2outpost.com/trade/20517599 - normal key + 1 ref (1.1), sold

http://www.tf2outpost.com/trade/20517687 - normal key + 1 ref (1.1), 1 sold

http://www.tf2outpost.com/trade/20541867 - normal key + 1.33 ref (1.1)

http://www.tf2outpost.com/trade/20448843 - normal key + 1.33 ref (1.1), sold

http://www.tf2outpost.com/trade/20531594 - normal key + 1.33 ref (1.1), 1 sold

http://www.tf2outpost.com/trade/20538434 - normal key + 1.33 ref (1.1), sold

http://www.tf2outpost.com/trade/20489012 - normal key + 1.44 ref (1.1), sold 1

http://www.tf2outpost.com/trade/20531070 - 10 ref (1.1)

http://www.tf2outpost.com/trade/20451430 - normal key + 1.66 ref (1.1), 1 sold

http://www.tf2outpost.com/trade/20502069 - normal key + 1.66 ref (1.1), 1 sold

http://www.tf2outpost.com/trade/20541725 - normal key + 1.77 ref (1.1)

http://www.tf2outpost.com/trade/20528079 - normal key + 1.88 (1.1)

http://www.tf2outpost.com/trade/20535406 - normal key + 2 ref (1.2), sold 2

http://www.tf2outpost.com/trade/20535575 - normal key + 2 ref (1.2)

http://www.tf2outpost.com/trade/20516730 - normal key + 2 ref (1.2)

http://www.tf2outpost.com/trade/20492342 - normal key + 2 ref (1.2), sold atleast 2

http://www.tf2outpost.com/trade/20534657 - normal key + 2 ref (1.2)

http://www.tf2outpost.com/trade/20430200 - normal key + 2 ref (1.2), sold 1 (Offered high five + 2 ref, 1.2)

http://www.tf2outpost.com/trade/20535530 - normal key + 2 ref (1.2)

http://www.tf2outpost.com/trade/20520796 - normal key + 2 ref (1.2)

http://www.tf2outpost.com/trade/20538937 - normal key + 2 ref (1.2)

http://www.tf2outpost.com/trade/20504707 - normal key + 2 ref (1.2), sold atleast 1

http://www.tf2outpost.com/trade/20530947 - normal key + 2 ref (1.2)

http://www.tf2outpost.com/trade/20539525 - normal key + 2 ref (1.2)

http://www.tf2outpost.com/trade/20540639 - normal key + 2 ref (1.2)

http://www.tf2outpost.com/trade/20451489 - normal key + 2 ref (1.2), sold a few

http://www.tf2outpost.com/trade/20437631 - normal key + 2 ref (1.2), sold a few

http://www.tf2outpost.com/trade/20508497 - normal key + 2 ref (1.2), sold 1

http://www.tf2outpost.com/trade/20437631 - normal key + 2 ref (1.2), sold a few

http://www.tf2outpost.com/trade/20443875 - normal key + 2.33 ref (1.2), sold 2

http://www.tf2outpost.com/trade/20496408 - normal key + 3 ref (1.3)

http://www.tf2outpost.com/trade/20425281 - normal key + 3 ref (1.3)

http://www.tf2outpost.com/trade/20471336 - normal key + 3 ref (1.3), 2 sold

http://www.tf2outpost.com/trade/20477480 - normal key + 3 ref (1.3)

http://www.tf2outpost.com/trade/20470335 - normal key + 3 ref (1.3)

http://www.tf2outpost.com/trade/20431456 - normal key + 4 ref (1.4)

Bought for 1 key + 1 ref:

http://www.tf2outpost.com/trade/20455621 - Bought 1 (1 ref in items)

http://www.tf2outpost.com/trade/20539373 - Bought 2

http://www.tf2outpost.com/trade/20535193 - Bought around 10 from 1 user

Failed to buy at 1 key:

http://www.tf2outpost.com/trade/20529544

http://www.tf2outpost.com/trade/20540472

http://www.tf2outpost.com/trade/20497173

http://www.tf2outpost.com/trade/20540136

http://www.tf2outpost.com/trade/20540090

http://www.tf2outpost.com/trade/20539983

http://www.tf2outpost.com/trade/20536566

http://www.tf2outpost.com/trade/20536913

http://www.tf2outpost.com/trade/20449380

http://www.tf2outpost.com/trade/20536855

http://www.tf2outpost.com/trade/20504627

http://www.tf2outpost.com/trade/20538512

http://www.tf2outpost.com/trade/20536934

http://www.tf2outpost.com/trade/20536365

http://www.tf2outpost.com/trade/20536280

http://www.tf2outpost.com/trade/20536234

http://www.tf2outpost.com/trade/20535096

http://www.tf2outpost.com/trade/20532094

http://www.tf2outpost.com/trade/20484717

http://www.tf2outpost.com/trade/20480742

http://www.tf2outpost.com/trade/20531766

http://www.tf2outpost.com/trade/20525545

http://www.tf2outpost.com/trade/20520354 - bot?

http://www.tf2outpost.com/trade/20518105

http://www.tf2outpost.com/trade/20525312

http://www.tf2outpost.com/trade/20521810

http://www.tf2outpost.com/trade/20514129

http://www.tf2outpost.com/trade/20457507

http://www.tf2outpost.com/trade/20510106

http://www.tf2outpost.com/trade/20490133

Extra (Buyers above 1 key):

http://www.tf2outpost.com/trade/20516813 - 1 key, 1 rec

http://www.tf2outpost.com/trade/20535157 - 1 key, 1 rec

http://www.tf2outpost.com/trade/20524106 - 1 key, 1 ref (1.1)

http://www.tf2outpost.com/trade/20536957 - 1 key, 1 ref (1.1)

Summary: Most people are selling within the 1.1-1.2 range. 1.1 sells rather quick while 1.2 sells aswell, if given some time. Most people are failing when doing 1:1's with normal keys and any on market are snatched quick. 1.3 is way to hard to sell to include it in the range.

So my suggested range is 1.1-1.2 keys.