Suggestion: Silver Cyclone Taunt: Yeti Smash at 9–10 keys

Can’t really get a prope value on the Big Kill. Though, they are selling on marketplace.tf for roughly 9-10 keys, so I suppose this would support the 10 key high end.

SALE #6 = 9 keys

https://backpack.tf/profiles/76561198070318593#!/compare/1518307200/1518393600

Sold for 8 keys and a key in stuff.

SUMMARY

Sales: 9 / 9 / 10 (supportive) / 10 keys

Sellers: 10 / 10 keys

https://gyazo.com/7bb9c320080d4a9fa35649ffa9928fa5

Going with 9-10 keys.

Apologies for the terrible lay-out! I did not know the lay-out would be this bad after copy-paste from Google Doc. I hope this is more clear ->

Silver Cyclone Taunt: Yeti Smash

New price: 9-10 keys

[proof below]

SALE #1 = 10 keys

https://marketplace.tf/items/1183;5;u3009

https://backpack.tf/item/6497176403

Sold for $18.89 ( / $1,90 ) = 10 keys

SALE #2 = 8 keys

https://marketplace.tf/items/1183;5;u3009

Sold for $16 ( / $1,90 ) = 8 keys.

SALAE #3 = invalid

https://backpack.tf/profiles/76561198132148941#!/compare/1517443200/1517961600

SCM.

SALE #4 = 9 keys

https://backpack.tf/profiles/76561198002186909#!/compare/1516665600/1516752000

Sold for 9 keys.

SALE #5 = supports high end

https://backpack.tf/profiles/76561198331794022#!/compare/1517097600/1517184000

Can’t really get a prope value on the Big Kill. Though, they are selling on marketplace.tf for roughly 9-10 keys, so I suppose this would support the 10 key high end.

SALE #6 = 9 keys

https://backpack.tf/profiles/76561198070318593#!/compare/1518307200/1518393600

Sold for 8 keys and a key in stuff.

SUMMARY

Sales: 9 / 9 / 10 (supportive) / 10 keys

Sellers: 10 / 10 keys

https://gyazo.com/7bb9c320080d4a9fa35649ffa9928fa5

Going with 9-10 keys.

Any real reason why you're excluding 8 here?

Realistically, the big kill sale will also support 8 keys. There's no way that Spec KS will sell for higher than Pro KS: https://backpack.tf/classifieds?item=Big%20Kill&quality=6&tradable=1&craftable=1&australium=-1&killstreak_tier=3

While there's no way to prove it, I'm quite sure the $16 was a quick sell. At the time it sold, taunts still had buyers at 7-8 keys and any taunt for sale at $16 on marketplace.tf would usually sell within hours.

If you want I could re suggest at 8-10

8-10 is probably the safest option, yeah. Even if the sale was a quicksell at the time, you're very likely to see bots undercutting eachother at 8 or even less in a few days' time for low tier taunts like these.