Sale 1-4:

https://marketplace.tf/items/tf2/30362;5;u6;strange

$66.00 / $1.78 = 37.08 keys

$77.00 / $1.8 = 42.78 keys

https://marketplace.tf/items/tf2/30362;5;u6

$55.79 / $1.81 = 30.82 keys

$36.03 / $1.81 = 19.91 keys

Sale 5:

Bulk

https://backpack.tf/profiles/76561198148511293#!/compare/1555977600/1556064000

Sale 6:

24 pure

https://backpack.tf/profiles/76561198102298516#!/compare/1557100800/1557187200

https://backpack.tf/profiles/76561198121830870#!/compare/1557100800/1557187200

Sale 7:

Bulk

https://backpack.tf/profiles/76561198356813033#!/compare/1557619200/1557705600

https://backpack.tf/profiles/76561198121830870#!/compare/1557619200/1557705600

Sale 8:

29 keys

sold with 2 keys for TF Logo Modest (31)

https://backpack.tf/profiles/76561198516017657#!/compare/1555027200/1555113600

https://backpack.tf/profiles/76561198165205268#!/compare/1555027200/1555113600

Modest mini:

https://marketplace.tf/items/tf2/139;5;u11

b/o 31:

https://imgur.com/a/XKCxxIg

Sale 9:

untrace

https://backpack.tf/profiles/76561198165205268#!/compare/1555113600/1555200000

https://backpack.tf/profiles/76561198120643050#!/compare/1555113600/1555200000

Sale 10:

Bulk

https://backpack.tf/profiles/76561198148511293#!/compare/1555891200/1555977600

https://backpack.tf/profiles/76561198120643050#!/compare/1555804800/1555977600

===================================================

Sales:

20,24,29,31,37,43

3 month unsold at 31 keys:

https://imgur.com/a/xBAWRpV

Buy order at 25 keys:

https://imgur.com/a/yxmONje