Owned, Gibcard.

https://backpack.tf/item/4038948895 - Nothing is traceable

https://backpack.tf/item/2602126798

Sale 1) Sold for a Killstreak Australium Sniper Rifle (~24 Keys) + ~7 Keys of Items + 2 Keys

https://backpack.tf/profiles/76561198254918432#!/compare/1542931200/1543017600

24 + 7 + 2 = 33 Keys

Sale 2) Sold for a Searing Plasma Private Eye (22 Keys)

https://backpack.tf/profiles/76561198184961155#!/compare/1541203200/1542240000

https://backpack.tf/profiles/76561198254918432#!/compare/1541203200/1541289600

Private Mini

https://backpack.tf/suggestion/5c2bc98d44325a5b213071e7 - 22 Keys

https://marketplace.tf/items/30003;5;u59 - Sold for $41.54 when Keys were ~$1.70 each and $58.46 when Keys were ~$1.79 each

41.54 / 1.7 = 24.4, which rounds to 24 Keys

58.46 / 1.79 = 32.65, which rounds to 33 Keys