I would pretty much have to know where a helmet came from before I decided if I would stick my melon in it. If you check motorcycle sites like Revzilla or Cycle Gear look at their discontinued helmets. I see them pretty often for $49 to $69. For what you are wanting it for the safety rating and such doesn't matter. If fogging up is ever an issue do a web search for a pinlock shield for helmets. I drag raced for years and ran dirt karts as well and never had a fogging issue. It's a small shield that attaches on the inside of your helmet shield and traps a small amount of air inside it which prevents it from fogging.

Hope you find a solution, a cold noggin isn't any fun.