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The Humble Weekly Bundle is the Simulators 3 bundle.
Pay what you want ($1 minimum for Steam keys) for:
Lunar Flight
Rescue – Everyday Heroes
Farming World
Post Master
Zoo Park
Pay $6 minimum for above plus:
Cities in Motion 2
Car Mechanic Simulator 2014
Pay $10 minimum for above plus:
Spacebase DF-9
All titles activate on Steam.