To easily gain Studs, select the "Escape From Echo Base" level. Choose any blaster character and Gonk droid. At the part where you see a square of silver Studs, with the first grapple hook press A. Build the computer thing and go through to the next room. Change to the Gonk droid when you start sliding down the hill and go back into the room you just came from. You will find 14,000 Studs. Repeat as desired.