What is a good cheap PA system for a beginner death metal vocalist?

Ok so Ive recently decided to be a death metal vocalist and Ive been kind of training the past year or so but I've been only doing it right for the past 6 months or so and still trying to get my highest pitch down (I have a voice similar to Carnifex's scott lewis) but its just i cant get that shriek down. Well anyway The way Ive been practicing is with my VOX guitar amp but it has a impedance adapter so i can connect my mic to it but im afraid that its just not enough and that my voice isnt coming out the way it should so i was wondering if someone can give me some tips as to getting an inexpensive PA system specifically for a begging death metal vocalist