need help deciding what is the best reflecting surface

what do you guys think is the best reflecting surfaces i can use for my walls and ceilings and for a reasonable price too

Strong(expensive) flat white paint or matt white paint cheap, although you may go for expensive shiny surface films, I'd rather spend the extra on an expensive light 400w hps instead of 250w, 600w instead of 400w, 1000w hps instead of 600w etc etc

flat white paint