Aside from the Super Story and Bonus arches in the cantina (about 40 bricks), you can unlock LEGO City at 60 bricks and a money generator at 99 bricks.
If you want to buy all the shop crap using the multipliers, do yourself a favour and purchase the Score x2 cheat first, then slowly build up to the "30 million" 10x cheat.
The "30 million" is actually less than you think if you have the score cheats stacked and in effect, so the greatest amount of money you need to actually collect is 3 million (for the Score 4x cheat at 6 million). This is because for each stud you collect, it's multiplied by the score multiplier cheat.
By the time of the score 6x cheat, you will be collecting 24x the amount of money, making the score 8x cheat (at 20 million) cost considerably less (divide total by 24).