A quick easy trick to getting a bunch of star tokens.
It Is Crazy
Just stand in front of a star token dispenser and pause the game. The timer on the star token dispenser will continue while the game is paused, so when you unpause, depending on how long you've left the game paused, you'll receive a flurry of star tokens all at once.
It's about 1 star token for every 8 or 9 seconds, just like when the game is running, but you don't have to fight off zombies while waiting for the tokens to come out.
This trick DOES NOT work for bomb dispensers, that timer pauses when you pause the game.