Resuggestion, thansk to Blaze for the info!

Challenge 19, Team F.L.A.M.B.E.S!

12th suggestion, made by Mikey!

Sale 1:

https://marketplace.tf/items/tf2/30572;5;u3015

https://backpack.tf/item/6302931359

June 22nd - $37.00

Keys were $1.98 that day, so 37 / 1.98 = 18.69, rounding to 19 keys.

Sale 2:

https://backpack.tf/profiles/76561198346618954#!/compare/1586044800/1586649600

https://backpack.tf/profiles/76561198176022675#!/compare/1586044800/1586131200

Untrace

Sale 3:

https://backpack.tf/profiles/76561198176022675#!/compare/1586131200/1586217600

https://backpack.tf/profiles/76561198141477086#!/compare/1586131200/1586217600

Untrace / Can't be found

Sale 4:

https://backpack.tf/profiles/76561198141477086#!/compare/1586131200/1586217600

https://backpack.tf/profiles/76561198141477086#!/compare/1586131200/1586217600

Untrace

Sale 5:

https://backpack.tf/profiles/76561198030137422#!/compare/1586304000/1586390400

https://backpack.tf/profiles/76561198340634356#!/compare/1586304000/1586390400

QS

Sale 6:

https://backpack.tf/profiles/76561198125958792#!/compare/1589846400/1589932800

https://backpack.tf/profiles/76561198340634356#!/compare/1589846400/1589932800

Untrace / Can't be found

Sale 7:

https://backpack.tf/profiles/76561198125958792#!/compare/1590105600/1590624000

https://backpack.tf/profiles/76561198118802562#!/compare/1590537600/1590624000

Sold for 8 keys, likely more. (under buyers)

Only one usable sale here.

Blaze’s PArt:

https://imgur.com/a/FupbmNn

https://steamcommunity.com/market/listings/440/Unusual%20Taunt%3A%20The%20Boston%20Breakdance?filter=Flames - seller at 14~ keys

https://marketplace.tf/items/tf2/30572;5;u3015 - new sale at $37 (18 keys)

https://imgur.com/a/t7c0m0G

https://bot.tf/stats/item?def=30572&q=5&ef=Infernal%20Flames&craft=1&aus=0&ks=0&

https://backpack.tf/profiles/76561198340634356#!/compare/1588723200/1588809600

https://bot.tf/stats/listings/4O9LK7DQ - https://bot.tf/stats/listings/Y9Q7W550 - was up at 11 keys + 20 ref for 5 days before selling

https://bot.tf/stats/listings/4P05G6Q0 - https://bot.tf/stats/listings/4WX16R5N - before that it was up at 11 keys + 30 ref for 3 weeks

i guess 11-19 could work here.