Sale 1:

https://backpack.tf/profiles/76561197999362239#!/compare/1562976000/1563062400

https://backpack.tf/profiles/76561198160856661#!/compare/1562889600/1562976000

Bulk

Sale 2:

https://backpack.tf/profiles/76561198367816851#!/compare/1567036800/1567123200

https://backpack.tf/profiles/76561198135225398#!/compare/1566950400/1567123200

Can trace ~2 keys in sweets

Sale 3:

https://backpack.tf/profiles/76561198135225398#!/compare/1567123200/1567296000

https://backpack.tf/profiles/76561198313943281#!/compare/1567209600/1567296000

Sold for Smoking Guad

Guad Mini:

https://backpack.tf/suggestion/5d6dcdc167807234e733581b

Suggestion for 11.5 keys

Sale 4:

https://backpack.tf/profiles/76561198313943281#!/compare/1567296000/1567382400

https://backpack.tf/profiles/76561198396576035#!/compare/1567296000/1567382400

Sold for spell + ~4 keys in sweets (items haven't loaded due to API)

Spell Mini:

https://backpack.tf/profiles/76561198137326742#!/compare/1566518400/1566604800

https://backpack.tf/profiles/76561198010332638#!/compare/1566518400/1566604800

Sold for 2 keys

Total is 6 keys

Sale 5:

https://backpack.tf/profiles/76561198253723121#!/compare/1566000000/1567209600

https://backpack.tf/profiles/76561198970367300#!/compare/1565913600/1566172800

SCM

Sale 6:

https://backpack.tf/profiles/76561198240320806#!/compare/1559433600/1560038400

https://backpack.tf/profiles/76561198050726553#!/compare/1559952000/1560038400

Bulky

Sale 7 - 9:

https://marketplace.tf/items/tf2/30014;5;u56

$26 / $1.84 = 14.13 keys <-- https://backpack.tf/item/2000338351

$16.06 / $1.83 = 8.78 keys

$26 / $1.82 = 14.29 keys

Sale 10:

https://backpack.tf/profiles/76561197970275557#!/compare/1566086400/1566259200

https://backpack.tf/profiles/76561198189381361#!/compare/1566000000/1566086400

Sweets make this bulky.

Sale 11:

https://backpack.tf/profiles/76561198189381361#!/compare/1566086400/1566172800

https://backpack.tf/profiles/76561198289602471#!/compare/1566172800/1566259200

Sold for C9 Bullets

used there

Total sales @:

6, 8.78, 11.5, 14.13, 14.29 keys

Poorly bumped seller at 12 keys,

buyers up to ~6 keys,

gonna take the large range of 9 - 14 keys