https://backpack.tf/profiles/76561198313582232#!/compare/1556150400/1556409600

https://backpack.tf/profiles/76561198269636307#!/compare/1556323200/1556409600

Massed Flies Climbing Commander (10.5 keys) + Poisonous Bubbles Trackman's Touchdown (4.5 keys) + Pro KS Strange Direct Hit (5 keys) + Spec KS Strange Festive Knife (6.5 keys)

26.5 keys, rounding to 27

https://gyazo.com/4fc681b6d7a6d5246e83d221230dac02 28 key buyout

https://backpack.tf/profiles/76561198269636307#!/compare/1556409600/1556496000

https://backpack.tf/profiles/76561198150191527#!/compare/1556409600/1556496000

Blizzardy Batter's Helm + 14 keys

https://backpack.tf/profiles/76561198164440171#!/compare/1556496000/1556668800

https://backpack.tf/profiles/76561198269636307#!/compare/1556582400/1556668800

The Helm was later resold for 15 keys. Using 29 keys.

https://backpack.tf/profiles/76561198173442901#!/compare/1555891200/1555977600

https://backpack.tf/profiles/76561198252999692#!/compare/1555891200/1555977600

Bulk

https://marketplace.tf/items/403;5;u9

March 9 - $49.90 / 1.80 = 28 keys

March 21 - $57.00 / 1.79 = 32 keys

https://gyazo.com/1d2601165b4ff4043fa932b219dee5ea

9 months for 30 keys