"for something that there is only 9 of, you think it would be worth more."

NEIN NEIN NINE NEIN

The sales:

Sale 1:[b]

Sale 2:

Sold for eerie doctors sack

http://backpack.tf/profiles/76561198177736182?time=1431449557 before

http://backpack.tf/profiles/76561198177736182?time=1431500400 after

Probably best to use this to update the eerie sack (1year outdated)

Sale 3:

Sold for bubbling geezer (~10) + 7 keys

http://backpack.tf/profiles/76561198004236703?time=1433969496 before

http://backpack.tf/profiles/76561198004236703?time=1434178800 after

0.9*10+7 = ~16

-> 16 keys

Sale 4:

Sold for aces wet works (~14)

http://backpack.tf/profiles/76561198176669829?time=1432882800 before

http://backpack.tf/profiles/76561198176669829?time=1433437997 after

Aces wet works is outdated, but the recent sales I can find on it are either for more outdated hats, or would be low outliers (Example: sold with 10+ keys for stormy slug)

Taking its outdated value

0.9*14 = ~13

-> 13 keys

Sales at 13, 15 and 16. Making a range with them

Constructive criticism welcome!

~Foamy :3