At the very beginning of the level "Darth Vader" you must run through a corridor crumbling into the lava. Its possible to pick up around 3000 studs before the end, however if you fall into the lava before going through the door , youll be taken back to the start, not lose any studs and all the studs you already picked up will regenerate. Its possible to make around 18,000 studs a minute by repeating this.