There is an old saying: You have a $10 head? Buy a $10 helmet.
That said, one of thee things you will find in helmet price differences is weight. Same DOT/Snell/whatever safety ratings, but one might be substantially lighter or breath better. . . . I have had high end lightweight helmets that breathed great and I have had $150 helmets. Both have taken some serious abuse. When racing, it was not uncommon to simply duck my head and tuck my arms and blast thru overhanging limbs. If you look at my helmets they will all have gouges from front to back where I have had limbs scratch them to pieces. I promise you, when you think you are going thru some light brush and find a good tree limb, it gives a good headache/neck ache.
Best suggestion I have is to go to Iron Pony in Columbus. I have found the best deals on riding gear at that store. Their catalog is okay, but in store specials are amazing. That is where we buy gear for the kids. $7 gloves, $10 pants/jerseys is about all you want to spend as the kids are growing. Plus, the store is an old K-Mart and huge. Just plain cool to see.