Too soon for another update? I don't know; this is my first time doing this.

Almost too easy to find at 2 keys, and incredibly common at 2.4.

Bazaar:

http://bazaar.tf/trade/224143 @ 2 Keys.

http://bazaar.tf/trade/230407 @ 2 Keys & 2 Refined

Outpost:

http://www.tf2outpost.com/trade/11091625 @ 2 Keys; unsold over a couple of hours though betting more on inactive seller than no interest.

http://www.tf2outpost.com/trade/11092480 @ 2 Keys; 1 sold one unsold over a couple of hours

http://www.tf2outpost.com/trade/11051544 @ 2.5 Keys; Unsold

http://www.tf2outpost.com/trade/10983202 @ 2 Keys 1.66 Refined; Unsold

http://www.tf2outpost.com/trade/11057777 @ 2 Keys; 2 sold within a day

http://www.tf2outpost.com/trade/11068512 @ 2 Keys; sold within a day

http://www.tf2outpost.com/trade/10931126 @ 2 Keys 2 Refined; unsold for 5 days

http://www.tf2outpost.com/trade/11094598 @ 2 Keys; A sell indicated in comments

http://www.tf2outpost.com/trade/11082452 @ 2 Keys; Unsold over several hours

http://www.tf2outpost.com/trade/11029513 @ 2 Keys 2.55 Refined; unsold 2 days

http://www.tf2outpost.com/trade/11087794 @ 2 Keys 2 Refined; unsold several hours

http://www.tf2outpost.com/trade/11085198 @ 2 Keys; Sold within several hours

http://www.tf2outpost.com/trade/11095539 @ 2 Keys 1 Refined; new

http://www.tf2outpost.com/trade/11047395 @ 2 Keys; Unsold, 1 day.

Most of the 2-key listings sold within the day but certainly not at a rate that they're disappearing. There's also a handful of 3-key listings with no attention paid to them other than 2-key offers.