Red boy's size 10 motocross outfit

My son is set on being a motocross dirt bike rider for Halloween. He already has a chest guard, helmet and gloves. He needs a red outfit (or shirt and pants), black boots and goggles. He will not really ride in them, so we can't afford to spend the prices for real motocross gear (at least new retail). He has special needs and doesn't understand that. He wears a boy's size 10 (he's very thin). Thank you!