been 6 days

Sale #1 and Sale#2 Sale#3 Marketplace.tf : https://marketplace.tf/items/tf2/30175;5;u58

Jul 20 , $75/1.81 = 41.4 keys, Aug 18 , $50/1.84 = 27.2 keys, Sep 16th $50/1.81 = 27.62 rounding to 28 keys

Sale #4 invalid

https://backpack.tf/profiles/76561197992953927#!/compare/1565136000/1566000000

https://backpack.tf/profiles/76561198018633251#!/compare/1564272000/1566086400

Sale #5

https://backpack.tf/profiles/76561198334712990#!/compare/1565827200/1565913600

https://backpack.tf/profiles/76561198334712990#!/compare/1565827200/1565913600

quicksold

Sale #6

https://backpack.tf/profiles/76561198045358232#!/compare/1566172800/1566259200 21 keys

https://backpack.tf/profiles/76561198314620824#!/compare/1566086400/1566345600

probably low, from glitched crate

Sale #7

https://backpack.tf/profiles/76561198259347037#!/compare/1560643200/1560902400

https://backpack.tf/profiles/76561198081308147#!/compare/1560643200/1560902400

clean orb planets crone’s dome, outlier

Sale #8

https://backpack.tf/profiles/76561197984688600#!/compare/1562371200/1562889600

https://backpack.tf/profiles/76561198081361662#!/compare/1562803200/1562889600

vivid plasma crit cloak

Sale #9

https://backpack.tf/profiles/76561198011321852#!/compare/1561161600/1561248000

https://backpack.tf/profiles/76561198081361662#!/compare/1561161600/1561248000

36 keys

Sale #10

https://backpack.tf/profiles/76561198011321852#!/compare/1558656000/1558742400

https://backpack.tf/profiles/76561198119225304#!/compare/1558742400/1559260800

bulk for sunbeams rotation sensation

Sale #11

Sold for cloud9 texas tin gallon + bubbling winter woodsman

https://backpack.tf/profiles/76561198189381361#!/compare/1566604800/1566691200

https://backpack.tf/profiles/76561198053912903#!/compare/1566604800/1566691200

Both hats are outdated.

Sale #12

Sold for pe toy soldier + 2 keys

https://backpack.tf/profiles/76561198002757046#!/compare/1568419200/1568505600

https://backpack.tf/profiles/76561197972404012#!/compare/1568419200/1568505600

Buyout was 23 keys

https://bot.tf/stats/listings/4PP5ZJ5E

Current sellers for the toy soldier

https://gyazo.com/79376aac6a3c50382f1c2070eaebd81f

Sale #13

Bulk for dbd mohawk

https://backpack.tf/profiles/76561198154446225#!/compare/1568073600/1568246400

https://backpack.tf/profiles/76561198002757046#!/compare/1568160000/1568246400

Sale #14

Likely sold for 24 keys + 5 refined

https://backpack.tf/profiles/76561198861619370#!/compare/1567036800/1567296000

https://backpack.tf/profiles/76561198154446225#!/compare/1567209600/1567296000

Histories don't match though.

Sale #15

Sold for 21 keys

https://backpack.tf/profiles/76561198193434709#!/compare/1566691200/1566777600

https://backpack.tf/profiles/76561198304302520#!/compare/1566691200/1566777600

Sale #16

Likely sold for 27 keys

https://backpack.tf/profiles/76561198337734785#!/compare/1569628800/1569715200

https://backpack.tf/profiles/76561198047445236#!/compare/1569542400/1569715200

Buyout was 29 keys

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

many thanks to Mindacos,мσяиιиgѕтαя, and pf

going with 24-28 as mindacos stated