Year old price.

Sale 1 :

Before ; http://backpack.tf/profiles/76561198004509501?time=1429513200

After : http://backpack.tf/profiles/76561198004509501?time=1429722340

Sold for a Bubbling Brainiac Hairpiece ( 20 keys ) + 1 key in items : 21 * 0.9 = 19 keys

Sale 2 :

Before : http://backpack.tf/profiles/76561198101385763?time=1428433596

After : http://backpack.tf/profiles/76561198101385763?time=1428476400

Sold for a Blizzardy Storm Your Worst Nightmare ( 20 keys ) + 1 key in items = 21 keys ( no overpay applied as mini is in pure )

Mini on the nightmare :

Before : http://backpack.tf/profiles/76561198131197518?time=1432969200

After : http://backpack.tf/profiles/76561198131197518?time=1433077134

Sold for 20 keys pure.

Thus taking the range of 19 to 21 keys.

Supportive criticism welcome.