Making a flat value, because this is where the majority of trades happen, with very few on each side.

New 1.33 trades, no old ones found

http://www.tf2outpost.com/trade/10803667 Selling for 1.33

http://www.tf2outpost.com/trade/10814187 Selling for 1.33

http://www.tf2outpost.com/trade/10807633 Selling for 1.33

http://www.tf2outpost.com/trade/10818651 Selling for 1.33

http://www.tf2outpost.com/trade/10783487 Wants 1.33 as said in a comment

http://www.tf2outpost.com/trade/10817291 Selling for 1.33

http://www.tf2outpost.com/trade/10797424 Selling for 1.33

http://www.tf2outpost.com/trade/10598388 Selling for 1.33, barely bumped

1.66 sellers with Moderate success

http://www.tf2outpost.com/trade/9256568 3 adds in 2 weeks, several 1.33 offers

http://www.tf2outpost.com/trade/10311432 3 adds in 3 weeks, several 1.33 offers

http://www.tf2outpost.com/trade/9224044 One add in a month, several 1.33 offers

http://www.tf2outpost.com/trade/9874802 2 recent adds, 1.33 offer

1.66 sellers with no success

http://www.tf2outpost.com/trade/10577767 Unsold at 1.66 for a week, in the comment says he's willing to do 1.33

http://www.tf2outpost.com/trade/10586055 Unsold at 1.66 for a week (4 of them)

1 ref sellers, quickly bought

http://www.tf2outpost.com/trade/10822922 1 ref

http://www.tf2outpost.com/trade/10805166 1 ref

1 ref buyers with moderate success

http://www.tf2outpost.com/trade/10203735 Has 11 adds in 3 weeks, best one

http://www.tf2outpost.com/trade/10618498 Has an add which ws retracted

http://www.tf2outpost.com/trade/10619156 One add in a week

http://www.tf2outpost.com/trade/10654097 Seems to have bought 2 for 1.33, unclear, check comments in suggestion linked at bottom.

[b] 1 ref buyers with no success

http://www.tf2outpost.com/trade/10496527 - Unbought for a week

CONCLUSION: 1 ref is possible to buy for but slow, 1.66 is possible to sell for but slow. There are very few successes on each side of 1.33. The fact that all 1.33 sellers are new shows that they get taken fairly quickly at 1.33.

Also thanks to Fyren6 for some proof and discussion, from his closed suggestion: http://backpack.tf/vote/id/51935c384bd7b87172000016