If you wanted to use things you have in, i think maybe the two extremes of innocent girl/complete slut (or even prostitute) could be a good way to go...(not at the same time, obviously! ) she'll probably have stuff (clothes, make up, hair stuff etc) that could be used for such scenarios...and it would also require very little expenditure in terms of your own outfit.
EXACTLY. It takes probably stuff she could find in her own home to make her from a schoolgirl to a slut. Or a librarian to a wench. For the more conservative or younger roles use very little makeup, put her hair up in braids or ponytails or even a bun, and have her wear flat shows for the sluttier older roles use lots of makeup and keep her hair long and flowing and wild, then put her in some heels. Honestly, that covers alot of ground with a little imagination.