I agree with Tony. Purchasing lights is a great part of everyone's development. Having said that, it does not make sense to break the bank too early if you can avoid it. Get used to photographing in good light. As you feel more comfortable and want to expand your light set-up, that is great. They provide an element of control that you cannot otherwise match.

There are lots of affordable light sets out there (you might want to check out the Shop Talk forum where there is plenty on this sort of thing).

James