Pumpkin Party Bazaar Bauble

Item 1

https://backpack.tf/item/9325597863

Sale 1:

https://backpack.tf/profiles/76561199125443371#!/compare/1664496000/1664668800

https://backpack.tf/profiles/76561198215813163#!/compare/1664409600/1665446400

12 Keys (B/O was 12 keys; 12 keys in compare)

Sale 2:

https://backpack.tf/profiles/76561198215813163#!/compare/1666742400/1666828800

https://backpack.tf/profiles/76561198343606728#!/compare/1666828800/1666915200

Bulk

Sale 3:

https://backpack.tf/profiles/76561198343606728#!/compare/1666915200/1667001600

https://backpack.tf/profiles/76561199081821087#!/compare/1666051200/1667001600

9 Keys + Sweet

Sale 4:

https://backpack.tf/profiles/76561199081821087#!/compare/1667001600/1667433600

https://backpack.tf/profiles/76561198886830410#!/compare/1647475200/1667347200

15 Keys

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Item 2

https://backpack.tf/item/9313594973

https://marketplace.tf/items/tf2/31112;5;u163

Sale 5:

19.99 / 1.98 = 10.09

10 Keys

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Sale Summary:

12 Keys

9 Keys

15 Keys

10 Keys

(Credit to Vege for rationale for the exclusion of Sale at 15 keys)

15 keys may end being a bit high here given the marketplace listing at ~10 keys was unsold for at least a month https://gyazo.com/3cc1749ef75fdb3eb9eb9a3b4685d924, and was also listed when the 15 sale happened.

The seller who sold at 15 was the same user who bought from marketplace shortly afterwards, not sure how to read into that.

Conclusion

9 - 12 Keys