That's the only thing I don't like about the really low end helmets, one size fits all. That usually means if you have a small head, you will look like a mushroom because the outter shell is large enough to fit the big heads. As far as price, though, the more expensive models usually cool you off better and look nicer. Protection is ABOUT the same, as long as they're approved by the same organization(s) such as ANSI or SNELL. I usually buy a mid-range helmet when it's on sale or closeout.