You need at least 2 000 dollars to do this cheat:
Go into scenery, and find the "Base Block".
Build a base block on the ground anywhere, and pile 5 more on it to make 6 base blocks piled on each other (use SHIFT to pile stuff). Right beside the 6 piled base blocks, build another 6 base blocks piled onto each other. When you have a 4 X 4 area of 6 piled base blocks, find the Bumper Cars ride, and place it right on the 4 X 4 base block assembly, so that it covers all of the "Bumper Cars ride". You will then be credited about $6,100. Then you can just destroy the ride, and repeat!