It really is the simplest things that amuse babies, and mobiles certainly don't have to be fancy or expensive to entertain them or bring them joy. In fact, here's a darling little butterfly mobile that you can make in less than an hour using a pair of disposable chopsticks and some old greeting cards.
A butterfly punch
A pair of disposable chopsticks
Old greeting cards (mine are from Tiny Prints)
1. Punch out butterflies, you'll need about 20-25.