Like a lot of the SimWhatever games, part of the experience is constructing a budget and slowly making money, which means that for a good chunk of the game you're going to have to deal with some pretty low cash flow, and that means that you won't be able to buy much of the fun stuff.
So, what to do? Do you plan your budget carefully, expand your course slowly, make smart investments, and watch as your pile of cash slowly but surely rises?
Yeah, you could do that, or you could hold down the Left Shift button and press the =/+ button on your keyboard. Every time you press it, you get 10,000 Simoleans. Do it enough times (or hold it in, if you're into that kind of thing) and you can rocket your cash flow up to some pretty ridiculous levels
Which means that you can do pretty much anything you want, now that you've been freed from the restraints of a 'budget'.
So go nuts!