1.5 keys is no longer a viable low end. People have been offering between 2 and 2.5, so there's no reason for it to stay in the range. They go unsold at 3 keys.

3 keys

http://www.tf2outpost.com/trade/8112720 - Unsold for 3 keys

http://www.tf2outpost.com/trade/8160858 - Unsold for 3 keys

2.5 keys

http://www.tf2outpost.com/trade/8108637 - Unsold for 2.5 keys

http://www.tf2outpost.com/trade/8052424 - Offer of 2.5 keys

http://www.tf2outpost.com/trade/7838630 - Offer of 2.5 keys

2 keys

http://www.tf2outpost.com/trade/6750059 - Offer of 2 keys

http://www.tf2outpost.com/trade/8138031 - Offer of 2 keys

http://www.tf2outpost.com/trade/8069338 - Bought for 2 keys

The curse of the 'retiring' hats continues.