I have worked in the motorcyle industry in the past. Having seen a hell of a lot of bikes that have been thrown down, and the matching helmets, DON'T scrimp on helmets, get the best you can afford.
Ever seen a car helmet, where the drivers helmet has smashed into the roll cage, even with the foam over the cage? I'm being brutal here for a reason. Don't be a temporary citizen please, any of you.
"You get what you pay for". The old adage applies here big time.