Classifieds:

http://i.imgur.com/W3POCz7.png (3-3.44 keys)

http://i.imgur.com/4XsKuFv.png (3.51-4 keys)

Unsolds at 4 keys:

http://www.tf2outpost.com/trade/26501743 trade up 5 hours

http://www.tf2outpost.com/trade/26502906 young

http://www.tf2outpost.com/trade/26496540 trade up almost a day

http://www.tf2outpost.com/trade/26473838 trade up 2 days

http://www.tf2outpost.com/trade/26498288 trade up almost a day

http://www.tf2outpost.com/trade/26503847 young

and everything beyond page 2 of search results seems to be 4+ keys, last bumped over 7 hours ago without being sold

Sellers around 3.7 keys:

http://www.tf2outpost.com/trade/26464940 (3 keys, 11 ref) reseller buying at 3 keys, trade has lots of traffic

http://www.tf2outpost.com/trade/26504112 (3 keys, 10 ref)

http://www.tf2outpost.com/trade/26501016 (3 keys, 9 ref)

Sellers <3.5 keys:

http://www.tf2outpost.com/trade/26502780 (3 keys, 8 ref)

http://www.tf2outpost.com/trade/26502899 (3 keys, 8 ref)

http://www.tf2outpost.com/trade/26502343 (3 keys, 7.88 ref)

http://www.tf2outpost.com/trade/26504103 (3 keys, 7.88 ref)

http://www.tf2outpost.com/trade/26493529 (3 keys, 7 ref)

http://www.tf2outpost.com/trade/26454585 (3 keys, 7 ref)

http://www.tf2outpost.com/trade/26430135 (3 keys, 6 ref)

http://www.tf2outpost.com/trade/26501946 (3 keys, 5 ref)

most are much less than a day old

Seller at 3 keys:

http://www.tf2outpost.com/trade/26502213 (unbumped)

Open to feedback, correct me or make a countersuggestion if you disagree.