We just recently got my 7 year old a Giant XTC Jr 20. It's a 7 speed and he can't quite gather the hand strength to go down in gears so we leave it in 4th for the most part. Cost is about $230 MSRP, but our Giant dealer also offers a 2 year window to trade in once he's ready for a 24" or full size bike. The bike being traded must be in decent condition, but the shop will tune it up and donate it to charity after he's done with it. The trade-in makes great economic sense for us since it's not that much more expensive than a department store bike for a lot higher quality rig. Plus he won't stop growing so I'm sure by the end of next summer he's gonna need a new bike anyway.