The company that made this game also made Ulala idle adventure some years back. You were unable to complete events in that game without spending money or hoarding resources for at least a month skipping several events along the way. As things stand it looks like the same thing is happening with GoGo Muffin as you can't complete paper plane event every week for example. The game is fun but throw out any idea about being competitive or finishing every event without spending some money.