NOTE: If you are curious why my last suggestion was closed...

"You should have all your proof at the time you post the suggestion"

I was gonna re-suggest anyway since wrong range xD

Tons of people selling for .22 - .33

Proof is available for .11 sellers although I did not find many trades for it as of now, may be re-used in-case you plan to re-suggest for the future

Classified listings

http://backpack.tf/stats/Unique/Mann%20Co.%20Strongbox/Tradable/Craftable/81

7 sellers for .22 , the rest lower than that

.11 - .15 sellers

http://www.tf2outpost.com/trade/17179749

http://www.tf2outpost.com/trade/17207588

http://www.tf2outpost.com/trade/17220049

http://www.tf2outpost.com/trade/17179749

http://www.tf2outpost.com/trade/17188627

http://www.tf2outpost.com/trade/17203014

http://www.tf2outpost.com/trade/17200633

http://www.tf2outpost.com/trade/17188627

http://bazaar.tf/trade/636648

http://bazaar.tf/trade/636517

http://www.tf2outpost.com/trade/17217774 (.15) (Multiple stock)

.22- .27 sellers

http://www.tf2outpost.com/trade/17217046

http://www.tf2outpost.com/trade/17184353

http://www.tf2outpost.com/trade/17219157

http://www.tf2outpost.com/trade/17191182

http://www.tf2outpost.com/trade/17205077

http://www.tf2outpost.com/trade/17179749

http://www.tf2outpost.com/trade/17205637

http://www.tf2outpost.com/trade/17214684

http://www.tf2outpost.com/trade/17207016

http://www.tf2outpost.com/trade/17209298

http://www.tf2outpost.com/trade/17218911

http://www.tf2outpost.com/trade/17214684

http://www.tf2outpost.com/trade/17212373

http://www.tf2outpost.com/trade/17214748

http://www.tf2outpost.com/trade/17184353

http://www.tf2outpost.com/trade/17201284

http://www.tf2outpost.com/trade/17197205

http://www.tf2outpost.com/trade/17209547

http://www.tf2outpost.com/trade/17183517

http://www.tf2outpost.com/trade/17191182 (Multiple stock)

http://www.tf2outpost.com/trade/17214684

http://www.tf2outpost.com/trade/17191614 (.27)

http://bazaar.tf/trade/633261

http://bazaar.tf/trade/636454

http://bazaar.tf/trade/636531

.33 sellers

http://www.tf2outpost.com/trade/17187808

http://www.tf2outpost.com/trade/17204516

http://www.tf2outpost.com/trade/17206590

http://www.tf2outpost.com/trade/17215243

http://www.tf2outpost.com/trade/17220189 (Apparently discounts for more crates)

http://www.tf2outpost.com/trade/17186709

http://www.tf2outpost.com/trade/17207387

http://www.tf2outpost.com/trade/17186627

http://www.tf2outpost.com/trade/17185803

http://www.tf2outpost.com/trade/17185514

http://www.tf2outpost.com/trade/17187956

http://www.tf2outpost.com/trade/17189794

http://www.tf2outpost.com/trade/17220025

http://www.tf2outpost.com/trade/17194916

http://www.tf2outpost.com/trade/17188791

http://www.tf2outpost.com/trade/17220049

http://www.tf2outpost.com/trade/17188791

http://www.tf2outpost.com/trade/17219765

http://www.tf2outpost.com/trade/17196238

http://www.tf2outpost.com/trade/17220241

http://www.tf2outpost.com/trade/17219765

http://www.tf2outpost.com/trade/17196238

http://bazaar.tf/trade/635653

http://bazaar.tf/trade/636820

http://bazaar.tf/trade/637248

I think that's enough proof

More proof is appreciated (in case more trades are added within the range since tons of listings are added every few hours or so...)