Taking from September 1

https://marketplace.tf/items/tf2/31103;11

$35.50 / $1.83 = 19.40 keys

$30.00 / $1.83 = 16.39 keys

$35.55 / $1.83 = 19.43 keys

$22.00 / $1.83 = 12.02 keys

$35.00 / $1.85 = 18.92 keys

$33.00 / $1.84 = 17.93 keys

$33.00 / $1.85 = 17.84 keys

$33.33 / $1.86 = 17.92 keys

$44.00 / $1.89 = 23.28 keys

https://steamcommunity.com/market/listings/440/Strange Hypno-eyes

https://steamcommunity.com/market/pricehistory/?country=US&currency=1&appid=440&market_hash_name=Strange Hypno-eyes

["Sep 01 2020 01: +0",31.927,"4"] = 14.07 keys

["Sep 02 2020 01: +0",33.632,"2"] = 14.50 keys

["Sep 03 2020 01: +0",34.03,"3"] = 14.67 keys

["Sep 04 2020 01: +0",34.476,"4"] = 14.92 keys

["Sep 05 2020 01: +0",28.906,"4"] = 12.57 keys

["Sep 05 2020 16: +0",30.461,"1"] = 13.24 keys

["Sep 05 2020 18: +0",18,"1"] = 7.83 keys

["Sep 05 2020 20: +0",30.472,"2"] = 13.31 keys

["Sep 06 2020 01: +0",33.85,"1"] = 14.71 keys

["Sep 07 2020 20: +0",33.85,"1"] = 14.65 keys

["Sep 08 2020 21: +0",32,"1"] = 13.91 keys

["Sep 09 2020 19: +0",33.898,"1"] = 14.74 keys

["Sep 10 2020 10: +0",33.506,"1"] = 14.50 keys

["Sep 10 2020 21: +0",31,"1"] = 13.42 keys

["Sep 11 2020 02: +0",33.95,"1"] = 14.63 keys

["Sep 11 2020 09: +0",27.459,"1"] = 11.84 keys

["Sep 11 2020 23: +0",30.007,"1"] = 12.93 keys

["Sep 12 2020 01: +0",33.779,"1"] = 14.56 keys

["Sep 12 2020 02: +0",40.839,"1"] = 17.68 keys

["Sep 13 2020 08: +0",41.44,"1"] = 18.10 keys

["Sep 15 2020 06: +0",34.5,"1"] = 15.07 keys

["Sep 15 2020 17: +0",34.987,"1"] = 15.02 keys

["Sep 15 2020 22: +0",39.36,"1"] = 16.97 keys

["Sep 17 2020 13: +0",39.46,"1"] = 17.23 keys

["Sep 19 2020 19: +0",39.99,"1"] = 17.39 keys

["Sep 22 2020 00: +0",45.004,"1"] = 19.15 keys

["Sep 22 2020 17: +0",32.16,"1"] = 13.63 keys

["Sep 23 2020 02: +0",49.45,"1"] = 20.86 keys

["Sep 24 2020 15: +0",45,"1"] = 19.48 keys

["Sep 26 2020 00: +0",50.195,"1"] = 21.64 keys

["Sep 26 2020 06: +0",37,"1"] = 16.02 keys

["Sep 26 2020 12: +0",45.997,"1"] = 19.66 keys

["Sep 26 2020 23: +0",63.255,"1"] = 26.69 keys

["Sep 28 2020 16: +0",37.386,"1"] = 16.11 keys

["Sep 29 2020 04: +0",36.24,"1"] = 15.55 keys

["Sep 30 2020 01: +0",38,"1"] = 16.31 keys

["Sep 30 2020 16: +0",40.345,"1"] = 17.39 keys

["Oct 01 2020 12: +0",49.446,"1"] = 21.41 keys

["Oct 02 2020 01: +0",44.85,"2"] = 19.93 keys

["Oct 02 2020 15: +0",44.718,"1"] = 19.70 keys

["Oct 03 2020 05: +0",36.176,"1"] = 16.01 keys

["Oct 03 2020 15: +0",36.176,"1"] = 16.01 keys

["Oct 04 2020 13: +0",36.731,"1"] = 16.04 keys

["Oct 04 2020 15: +0",25.541,"1"] = 11.40 keys

["Oct 05 2020 08: +0",28.61,"1"] = 12.83 keys

https://backpack.tf/classifieds?item=Hypno-eyes&quality=11&tradable=1&craftable=1&australium=-1&killstreak_tier=0

https://gyazo.com/5af3aab662823c610c2045df20d70035

10-12.5 key buyers

https://gyazo.com/dd26a92f7e7406d000b52ad1f5415e71

Marketplace buyers $10-20, which goes up to like 11-12 keys

https://gyazo.com/4f0b8a5e6dbcc7c121c9350f5f582251

SCM buyers up to $28, which does up to like 12 keys

Sales:

7.86

11.4

11.84

12.02

12.57

12.83

12.93

13.24

13.31

13.42

13.63

13.91

14.07

14.5

14.5

14.56

14.63

14.65

14.67

14.71

14.74

14.92

15.02

15.07

15.55

16.01

16.01

16.02

16.04

16.11

16.31

16.39

16.97

17.23

17.39

17.39

17.68

17.84

17.92

17.93

18.1

18.92

19.15

19.4

19.43

19.48

19.66

19.7

19.93

20.86

21.41

21.64

23.28

26.69

without rounding for the halves:

7x under 13/buyers

5x at 13 keys

10x at 14 keys

3x at 15 keys

8x at 16 keys

7x at 17 keys

2x at 18 keys

7x at 19 keys

5x above 20 keys

looks pretty common at 13-14 and at 17-19

going with 13-19 keys