Classifieds at the time of posting this suggestion.

Unsolds are based on how long the listing has been up; Listing has been up 5 days and item been in the sellers inventory for 8 days? It has been unsold for 5 days.

The age of the listing(s) are shown in the screenshots rather than the last bump - Unsolds and item histories are presented in chronological order according to the screenshot(s).

x1 for sale at 2.3 Keys - http://i.imgur.com/rcMLxwb.png

Unsold for 21 hours http://backpack.tf/item/5059011134

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x1 for sale at 2.4 Keys - http://i.imgur.com/CMkMl9U.png

Unsold for 3 days http://backpack.tf/item/1959125636

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x1 for sale at 2.45 Keys - http://i.imgur.com/RtYlyvm.png

Unsold for 3 days http://backpack.tf/item/5037074445

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x1 for sale at 2.5 Keys - http://i.imgur.com/uSlVBb9.png

Unsold for 6 days http://backpack.tf/item/1423894025

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x1 for sale at 2.7 Keys - http://i.imgur.com/CYh7vkG.png

Unsold for 8 days(Duplicated) http://backpack.tf/item/1573455797

Outpost sellers.

http://www.tf2outpost.com/trade/28440871 - 2.3 Keys - Unsold for 2 days - Autobumper.

http://www.tf2outpost.com/trade/28406493 - 2.3 Keys - Unsold for 2 weeks.

http://www.tf2outpost.com/trade/28440871 - 2.4 Keys - Unsold for 2 days - Autobumper.

http://www.tf2outpost.com/trade/28382465 - 2.7 Keys - Unsold for 3 weeks - Autobumper.

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