Credits to Cashew!

Miami Head Warmer

New price: 29-34 keys

[proof below]

SALE #1 = invalid

https://backpack.tf/profiles/76561198145393210#!/compare/1498089600/1498348800

Sold to a quickbuyer for 22 keys + 4 ref

SALE #2 = invalid

https://backpack.tf/profiles/76561198231530440#!/compare/1497052800/1497225600

Bulk.

SALE #3 = invalid

https://backpack.tf/profiles/76561198153402711#!/compare/1497139200/1497225600

Sold to a quick buyer for 25 keys.

SALE #4 = 29 keys

https://backpack.tf/profiles/76561198145393210#!/compare/1497916800/1498003200s

Sold for a Max Head + Australium Stickybomb Launcher = 29 keys

SALE #5 = 34 keys

https://backpack.tf/profiles/76561198265422634#!/compare/1498435200/1498694400

https://backpack.tf/profiles/76561198026129220#!/compare/1498435200/1498521600

Sold for a Terror-Watt Headwarmer + Australium Blutsauger + 4 keys + some ref = 34 keys

SALE #6 = 29 keys

https://backpack.tf/profiles/76561198057671085#!/compare/1494115200/1494288000

Sold for an Australium Flamethrower + Australium Ambassador + sweets = ~29 keys

SUMMARY

Sales: 29 / 29 / 34 keys

Sellers: 30 / 31 keys

Going with 29-34 keys.