When you exit of the Gryffindor Tower notice the object in the corner. Hit it with Flipendo and three Beans will appear. Go around the corner and walk at least three steps away. Return and cast Flipendo again to get three more Beans. Repeat this to get as many Beans as needed.

Use the Nimbus 2000 Broomstick and fly above Hogwarts. Fly through the rings to get free Beans. A blue ring gives 10 Beans, a yellow ring gives 1 Bean, a red ring gives 3 Beans and a green ring gives 2 Beans.

When you go outside of Hogwart's, go to the tree where you walk through a long hallway and Flapendo it to get as many Beans as needed.