I grew up on and beat the crap out of a huffy BMX bike that went through two of my older brothers first. If it broke I learned how to fix it and if I would have had a younger brother it would have been handed down to him. Point being you don't need to spend $400 on a bike for a 6 year old.

Don't let the bike snobs on here scare you away from an x-mart bike for your kid.