There isn't a whole lot of difference between snowboard helmets. They all have compressed styrofoam innards that act as the shock-absorbing material.... so really all you're paying for is the differences in the plastic shell (shape, finish) and any extra options (headphones, etc).
Having said that, snow helmets are a $#@#$ rip-off.
Motorcycle helmets have:
- More compressed styrofoam
- Larger shells (often made out of kevlar or fiberglass)
- More plush padding and cushioning
- Better painted designs
- Plastic visors (some of them are anti-fog)
...and they have to pass DOT testing in order to be sold as motorcycle helmets in most states.
Cheap motorcycle helmets can be found for $100. Compare that to snowboard/ski helmets which have far fewer features/material that sell for ~$80.
My advice would be to find a $40-or-less snowboard helmet, or just use a skateboard helmet. Spending more than that doesn't make sense to me.