What should you buy when making a movie at a budget of 15 thousand dollars?

Honestly, you need to spend it all on film. 15 g's won't be enough for anything usefull, except for extra film incase you make a mistake. I've been there man, and 15 g's barely covers the film alone. I'm assuming this is your first film since you have such little backing. Number one fault of a newbie director is not shooting enough film. A good movie can exist of nothing but one room and one character, the only thing else you need is skill..... Besides film, obviously... :)