Ain't it typical.

Sales

Sale 1: Sold for 7 keys

https://backpack.tf/profiles/76561198024999234#!/compare/1597622400/1598054400

https://backpack.tf/profiles/76561198839890152#!/compare/1597449600/1597622400

Sale 2: Untrace

https://backpack.tf/profiles/76561198299169464#!/compare/1578614400/1591488000

https://backpack.tf/profiles/76561198024999234#!/compare/1591401600/1591660800

Probably the first marketplace sale below.

Exchanges with mannco store.

https://backpack.tf/item/5360211522

Marketplace

https://marketplace.tf/items/tf2/30839;5;u3020

June

$10 on June 8 (10/1.98 = 5~)

https://manic.tf/keyprice/?at=2020-06-08

Listings during the time: https://bot.tf/stats/listings/MNR8K0XQ

https://bot.tf/stats/listings/4ZPRG6G1

August

$16.26 on August 18 (16.26/1.79 = 9~)

https://manic.tf/keyprice/?at=2020-08-18

https://backpack.tf/item/5523026324

Listings during the time: https://bot.tf/stats/listings/MNR5E168

https://bot.tf/stats/listings/4ZP2NXX1

Classifieds

https://gyazo.com/5598451297d144e6883770b1ada4d109

Marketplace listing

https://marketplace.tf/items/tf2/30839;5;u3020

https://backpack.tf/item/7249517960

Seller at $16 for 2 days.

https://bot.tf/stats/listings/Y7927899

$16/1.88 = 8.51~

Summary

Sales at 7.

Marketplace sales at 5 and 9.

Conclusion

Seller is 1.5 days old only, but with current key prices, it is lower than the sale at 9.

Going to go with 5-7 for now.

The seller at $16 is still there, now for about 9 days.

https://gyazo.com/e85c7500e7b30aaaca10dee1ffe20a88

For the last week, the prices of the key were around 1.82-1.84~ https://marketplace.tf/items/tf2/5021;6

Taking the average of 1.83. 16/1.83 = 8.74~ which is still under the sale of 9.

Going to stick with current suggestion for now.