3.7 keys = 3 keys 3 ref at current key price

Thought about making it 3.5-4 but didn't have proof for 3.5 (3 keys 2.11 ref).

Some supply, not big demand.

Supply:

http://www.tf2outpost.com/trade/9603359 -> quicksell 3 keys 3 ref; only 1 offer of 3 keys, rejected; probably sold because doesn't have it in backpack

http://www.tf2outpost.com/trade/9620910 -> reply to brandenc40 comment: "3 keys + 3 ref and its a deal"; probably sold because doesn't have it in backpack

http://www.tf2outpost.com/trade/9517309 -> rejected offer of 3 keys; another rejected offer of 3,5 keys in items; still has it in backpack

http://www.tf2outpost.com/trade/9487729 -> 4 keys quicksell; 1 added; still has it in backpack

http://www.tf2outpost.com/trade/9683350 -> selling for 4 keys; no offers; still has it in backpack

http://www.tf2outpost.com/trade/9623875 -> selling for 4 keys; no offers; not in backpack

http://www.tf2outpost.com/trade/9678838 -> selling for 4 keys; no offers; still has it in backpack

http://www.tf2outpost.com/trade/9679634 -> selling for 4 keys; no offers; still has it in backpack

http://www.tf2outpost.com/trade/9563006 -> selling for 4 keys; no offers; still has it in backpack

http://www.tf2outpost.com/trade/9608080 -> offer of 3 keys; still has it in backpack

Demand (no lowballers or no offer threads):

http://www.tf2outpost.com/trade/9126753 -> buying for 3 keys 3 ref; hidden offer for 3 keys 3 ref

http://www.tf2outpost.com/trade/6134507 -> fresh offer of 4 keys, no response; 2 month old offer of 3 keys 2 ref

Only this. Other trades are either old or lowballed with no offers.

/just saying, it's my first suggestion, hopefully right one.