Once more.

Bot.tf: https://bot.tf/stats/item?def=30525&q=6&ef=&craft=1&aus=0&ks=0 | https://imgur.com/a/RoNTkgT

Two sales for 2.3 Keys

STN currently pays 2 Keys: https://stntrading.eu/item/tf2/The%20Creature's%20Grin | https://imgur.com/a/rKe5jos

General Sales:

Sale 1:

https://backpack.tf/item/3184441396

Sold for 2 Keys & 2.33

https://backpack.tf/profiles/76561198865420860#!/compare/1566432000/1566604800

https://backpack.tf/profiles/76561197995880156#!/compare/1566432000/1566691200

Sale 2:

https://backpack.tf/item/3181585441

Sold for 2 Keys & 6

https://backpack.tf/profiles/76561198855140008#!/compare/1566000000/1566172800

https://backpack.tf/profiles/76561197995880156#!/compare/1566000000/1566172800

Marketplace Sales:

https://marketplace.tf/items/tf2/30525;6

Sale 3:

Sold on Sep 14th for $4.5 x2, Keys were $1.84

2.4 Keys

Sale 4:

Sold on Aug 19th for $4.5, Keys were $1.84

2.4 Keys

Sales 5-9:

Sold on Aug 11th, 13th, 15th & 18th for $4.45, Keys were $1.83, $1.82, $1.83 & $1.84

2.5 Keys, 2.5 Keys, 2.5 Keys, 2.4 Keys

Sale 10:

Sold on Aug 10th for $2.15, Keys were $1.81

1.2 Keys

Sale 11:

Sold on Aug 6th for $3.8, Keys were $1.84

2.1 Keys

Sales 12-13:

Sold on Aug 3rd & 1st for $4.45, Keys were $1.82, $1.8

2.4 Keys, 2.5 Keys

Sale 14:

Sold on Jul 28th for $3.2, Keys were $1.8

1.8 Keys

Sale 15:

Sold on Jul 23rd for $4, Keys were $1.81

2.2 Keys

Sales 16-19:

Sold on Jul 7th for $3.8, Keys were $1.83

2.1 Keys

Summary of Sales:

3x 2.5

5x 2.4

2x 2.3

1x 2.2

5x 2.1

2x 2

1x 1.8

1x 1.2

Using 2.4 as the high end as it does seem to still sell at the price based on MP, leaving 2.5 out as they're outliers

Going with 2.3-2.4