Revised suggestion, based off more accurate math and sales in an attempt to finally price this item.

Marketplace.tf Sales:

https://marketplace.tf/items/tf2/31074;5;u130 There have been 3 sales of late, on Sept. 1 for $44 USD, on September 3 for $42.22, and on September 20th for $44 again. I assume that this is due to the effect, Twisted Radiance.

https://marketplace.tf/items/tf2/31074;5;u130

$27 / $2.00 = 13.50 keys

$21.62 / $1.92 = 11.26 keys

$27.99 / $1.98 = 14.14 keys

$25 / $1.98 = 12.63 keys

$32.5 / $1.91 = 17.02 keys

$15 / $1.89 = 7.94 keys

$26 / $1.84 = 14.13 keys

$26.8 / $1.85 = 14.49 keys

$29 / $1.86 = 15.59 keys

Sales you mentioned w/ correct math:

$44 / $1.83 = 24.04 keys

$42.22 / $1.84 = 22.95 keys

$44 / $1.85 = 23.78 keys

https://imgur.com/a/8Ib3ZMz - 2 bot.tf sales at 15, 1 buy at 11

https://backpack.tf/profiles/76561198341171690#!/compare/1598313600/1598400000

https://backpack.tf/profiles/76561198335791307#!/compare/1596405600/1596492000

Sales at:

8

11 (x2)

13

14 (x4)

15 (x2)

16

17

23

24 (x2)

23/24 seem high while 11 and under are low due to buyers, so 13 - 17 should work here.

Credit to Xergoyf for additional research in helping me price this.