BTW, I wouldn't worry about getting an alternative to the 50mm f2 - even though it's a cheapie, it's one of the very finest lenses Nikon ever made.
And it is true, the faster lenses are quite a bit more expensive. If I were you, I'd get a couple of inexpensive ones, say a telephoto and a wide angle, and see how you enjoy using the different perspectives. Given where you are right now in the hobby, I would certainly NOT spend $500+ on fast lenses before you have a much better understanding of what you like to shoot, and what tools you need to do it well. You could easily get a used moderate speed wide angle (24 or 28mm) and a telephoto (like a 105mm or 135mm) for around $100 combined and this will be all you need to determine where, if anywhere, you would wish to invest some REAL money in the future, on really top end high speed lenses.
And if you buy used lenses wisely, and you decide that you prefer something different, you can end up selling what you bought for nearly as much as you paid for them.