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).

x3 for sale at 3.3 Keys - http://i.imgur.com/emhAVfz.png

Unsold for 1 day http://backpack.tf/item/2378870174

Unsold for 11 days http://backpack.tf/item/2448355224

Unsold for 2 days http://backpack.tf/item/2484971218

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x1 for sale at 3.5 Keys - http://i.imgur.com/RIoA5Gj.png

Unsold for 5 days(Painted Lime) http://backpack.tf/item/2348270577 > User also has an Outpost trade;

http://www.tf2outpost.com/trade/28443864 - "around backpack.tf price" - Young - Autobumper.