Sale 1:

https://backpack.tf/profiles/76561199000901353#!/compare/1623715200/1624060800

https://backpack.tf/profiles/76561198035332989#!/compare/1623974400/1624060800 - Sold for Professional Killstreak Original with Pumpkin Bombs Spell? (Items likely missing)

Sale 2:

https://backpack.tf/profiles/76561198362915001#!/compare/1624838400/1625270400 - Sold for 24 keys + 33.33 refined + 15.66 ref in sweets = 24.8 rounding up to 25

Sale 3:

https://backpack.tf/profiles/76561198363628327#!/compare/1626048000/1626134400

https://backpack.tf/profiles/76561198362915001#!/compare/1626134400/1626220800 - Untraceable

Sale 4 :

https://backpack.tf/profiles/76561198363628327#!/compare/1626307200/1626393600

https://backpack.tf/profiles/76561199125443371#!/compare/1626307200/1626393600 - Sold for unknown amount of keys

Sellers:

https://imgur.com/a/tiI20mA - Unsold at 30 keys for over 2 weeks

No other sales and 30 keys doesn't appear possible.

Going with 25 flat.