Score modifiers are a great way to make more studs. Aim to get the red bricks that unlock each one, and activate all of the ones you've unlocked simultaneously. The purple stud, which appears next to the shop, usually gives you 150,00 or so. So, with modifiers:
2 x 15,000=30,000 2 x 4 x 15,000=120,000 2 x 4 x 6 x 15,000=720,000 2 x 4 x 6 x 8 x 15,000=5,760,000 2 x 4 x 6 x 8 x 10 x 15,000=57,600,000
That's quite a lot of studs! Also, unlocking all the characters/hints only costs around 4,000,000 total, so you're set.
After unlocking Yoda, go into freeplay and pick any of the RTS type levels or select the Geonosis Arena. If you are on a RTS level, this will be extremely simple. Wait until a group of droids is sent after and you and just toss your lightaber.
Once you get onto the Separatist ship, there is a platform you can raise towards the back. Use a jedi's force to get across to the other side, or a droid can also raise a different platform using the panel. Once you get all the way to the right you'll find a bunch of gold bricks on the ground. You need around 30 to build the door. After building the door, get into the elevator and the level will be right there.
Unlocking the trophy itself is pretty simple, but unlocking the character is where people have trouble. To unlock him, just collect all the minikits on the level "Shadow of Malevolence". For the actual trophy, land the space ship in the main hub.
First, reach the General Grievous campaign, then Chapter 5. Once there, play until you get control over the rookies. One of them has the machine gun. You will eventually come to a hallway with tons of droids flooding in. Start going insane and killing as many as you can. They keep respawning and, even if you die, the counter does not reset.
To defeat the Zillo Beast, gather about 100,000 credits -- you may not need that much, but just to be safe get it anyway. Go to every build area and build a turret on each one. Check every build area and find the one that will let you build tanks. Build a bunch of X-130 Tanks and you're done. All you have to do now is watch (and maybe help a little).
You must complete 5 loop-the-loops, 5 backflips, and 5 corkscrews. To perform these, get into a ship and simply have double tap the joystick twice in the corresponding direction. So, 2x away from the cockpit, 2x towards the cockpit, and 2x any direction sideways. Do those 5 times for each on any mission or on the main hub to unlock the trophy.
If you explore your hub you will find a hanger. You pick a ship then you will take off and be in open space. If you go right all the way you will find a Confederate ship. You can board it and start purchasing the characters over there. If you are a republ