First suggestion, so comments/constructive criticism welcome.

Sales only on the Steam Community Market:

http://i.imgur.com/zOcQ03n.png

None on backpack (old/low buy orders, too):

http://i.imgur.com/tALvd2c.png

or bazaar:

http://i.imgur.com/1gVIxBs.png

or outpost:

http://i.imgur.com/sLkVxuF.png

http://i.imgur.com/kT6PbL2.png

Bought one myself 10/30/16 on SCM for $35.13 or ~16 keys, 6 ref;

Before that, another was bought for $29.99 or ~13 keys, 21 ref:

http://i.imgur.com/dzK4OhK.png

Next one for sale starts at $39.99 or ~18 keys, 12 ref

If this is too much, feel free to let me know in comments.

P.S. Only 125 of these crates exist:

http://i.imgur.com/ih1ky68.png

That's only 1 more than Golden Pans:

http://i.imgur.com/UsPMnR1.png

lowest sale on record: $29.99 or ~13 keys, 21 ref (13.75 keys)

next one for sale: $39.99 or ~18 keys, 12 ref (18.5 keys)