Classifieds at the time of posting this suggestion.

The age of the listing(s) are shown in the screenshot(s) rather than the last bump.

Unsolds and item histories are presented in chronological order according to the screenshot(s).

x3 for sale at 4 Keys - http://i.imgur.com/dFfy0h1.png

Unsold for 22 hours http://backpack.tf/item/5041601350

Unsold for 3 days http://backpack.tf/item/4969907643

Unsold for 3 days http://backpack.tf/item/5033638521

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x1 for sale at 4.5 Keys - http://i.imgur.com/Z6seInQ.png

Unsold for 5 days http://backpack.tf/item/5049046872

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x5 for sale at 5 Keys - http://i.imgur.com/QkKGAJg.png

Unsold for 10 days http://backpack.tf/item/5010625721

Unsold for 14 days http://backpack.tf/item/4964833901

Unsold for 4 days http://backpack.tf/item/5056029574

Unsold for 13 days http://backpack.tf/item/5065476045

Unsold for 7 days http://backpack.tf/item/5076790823

Outpost sellers.

http://www.tf2outpost.com/trade/28490477 - 4 Keys - Unsold for 2 days.

http://www.tf2outpost.com/trade/28426637 - 4 Keys - Unsold for 4 weeks - Autobumper.

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http://www.tf2outpost.com/trade/28478520 - 5 Keys - Unsold for 1 week.

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http://www.tf2outpost.com/trade/28488982 - 5 TF2 Keys/4 CS:GO Keys - Unsold for 3 days.

I am excluding all trades on Outpost that haven't been bumped in 1 day or more.