Using last month.

The Sale:

Sold for $23.50 on Marketplace.tf

https://marketplace.tf/items/30570;5;u3010

23.50/1.97 = ~11.9

X = 12

Sellers:

13 keys:

https://i.imgur.com/YJkDywy.png

https://backpack.tf/item/4426790953

20 keys:

http://www.tf2outpost.com/trade/29558830

285 keys:

http://www.tf2outpost.com/trade/28672999

Sales at:

12

In my last attempt at this suggestion, I had a sale at 14 pure which was excluded due to large amounts of cheaper sellers. Most of these sellers are gone or have been banned now, but the sale is now over a month old, so it can be excluded anyways.

The seller at 11 from the last attempt at this suggestion is now gone, due to the user not bumping. They most likely didn’t visit the site since listing the item for sale (despite being active on steam), so I doubt the time they had it listed would matter much here.

No new sales have occurred since last time.

Going with 12 flat.