Sale 1:

https://backpack.tf/profiles/76561198323565601#!/compare/1583193600/1583280000

https://backpack.tf/profiles/76561198170165054#!/compare/1583280000/1583366400

Sold for 13 keys

sale 2:

https://backpack.tf/profiles/76561198095804548#!/compare/1581897600/1584057600

https://backpack.tf/profiles/76561198073611549#!/compare/1581811200/1581897600

untrace

Sale 3:

https://backpack.tf/profiles/76561198073611549#!/compare/1582156800/1582243200

https://backpack.tf/profiles/76561198363395191#!/compare/1582156800/1582243200

QS(?)

Sale 4:

https://backpack.tf/profiles/76561198242646048#!/compare/1580860800/1581724800

https://backpack.tf/profiles/76561198047433991#!/compare/1581465600/1581638400

Untrace

sale 5:

https://backpack.tf/profiles/76561198047433991#!/compare/1582588800/1584057600

https://backpack.tf/profiles/76561198998082956#!/compare/1583971200/1584144000

Sold for 13 keys

Sale 6:

https://backpack.tf/profiles/76561198998082956#!/compare/1583971200/1584144000

https://backpack.tf/profiles/76561198095722606#!/compare/1584057600/1584144000

Sold for 10 keys immediately after Sale 5

Sale 7:

https://backpack.tf/profiles/76561198095722606#!/compare/1584144000/1584230400

https://backpack.tf/profiles/76561198329940613#!/compare/1584057600/1584230400

Sold for DBD Hottie

hottie Mini:

https://backpack.tf/suggestion/5ea1eed3de1f5722bb4bd5be

Suggestion for 14 keys

sale 8:

https://backpack.tf/profiles/76561198329940613#!/compare/1584057600/1584230400

https://backpack.tf/profiles/76561198316941182#!/compare/1584057600/1584230400

Sold for Steaming Commander + ~1 key in sweets

use there

sale 9:

https://backpack.tf/profiles/76561198316941182#!/compare/1584230400/1584576000

https://backpack.tf/profiles/76561198144472459#!/compare/1584230400/1584403200

Sold for 10 keys

sale 10:

https://backpack.tf/profiles/76561198144472459#!/compare/1584403200/1584489600

https://backpack.tf/profiles/76561198157747807#!/compare/1584403200/1584489600

Bulky / use there

sale 11:

https://backpack.tf/profiles/76561198157747807#!/compare/1585440000/1585699200

https://backpack.tf/profiles/76561198057124378#!/compare/1585526400/1585612800

Sold for 10 keys

Sale 12:

https://marketplace.tf/items/tf2/152;5;u59

$20.99 / $1.78 = 11.79 keys

$19.95 / $1.72 = 11.60 keys

$19.95 / $1.79 = 11.15 keys

Total sales @:

10, 10, 10, 11, 12, 12, 13, 13, 14 keys

buyers up to ~9 keys,

sellers down to 15 keys,

considering Sale 6,

taking 10 - 13 keys