I sure hope you don't let your kids ride in the street- they might slow down traffic
It will be interesting to see how your attitude changes when you see cars playing with your kids on their bikes.
Keep them safe. If you buy a bike at walmarts or some other large chain go over the bike well yourself- they have probably been essentially thrown together. Check every bolt, check wheel alignment, check brake adjustments, etc. That is one advantage to buying a bike at a good shop- the bike may be almost the same, but it will be assembled with care and experience.
Then buy a good bike helmet that fits. Not one that will fit his brother, or that he can grow into- one that fits now. This I would get at a true bike shop, no matter where I bought the bike. Some of the better helmet used to have an upgrade program for kids- you could exchange helmets for a larger size for like $25- Bell had it in the past and we used it for both of my kids as they were growing up.
Enjoy the sport- but keep them safe.
Gary
gchappel