Brotherhood of Starms

https://backpack.tf/item/5268064843

Sale 1) Sold for a Sunbeams Burning Bandana (67.5 Keys) + 1 Key + ~1 Key of Items

https://backpack.tf/profiles/76561198173442901#!/compare/1506038400/1506124800

67.5 + 1 + 1 = 69.5, which rounds to 70 Keys

Bandana Mini

https://backpack.tf/suggestion/5a2d4660cf6c753c814f4f80 - 67.5 Keys

Sale 2) Bulk sale for something

https://backpack.tf/profiles/76561198150783829#!/compare/1506902400/1506988800 - Seller's Backpack

https://backpack.tf/profiles/76561198208055117#!/compare/1506470400/1506988800 - Buyer's Backpack

Sale 3) Sold for a Duped Burning Flames Pyro's Beanie (47 Keys) + 10 Keys

https://backpack.tf/profiles/76561198208055117#!/compare/1508457600/1508803200

47 + 10 = 57 Keys

Beanie Mini

Sold + Specialized Killstreak Australium Flame Thrower (~16 Keys) + ~3 Keys of Items for a Poisoned Shadows Firewall Helmet (66 Keys)

https://backpack.tf/profiles/76561198164704162#!/compare/1506816000/1506902400

66 - 16 - 3 = 47 Keys