Kids can be hard on bicycles. I have a clear, embarrassing memory of myself aged about 5 burying my bicycle in the sandpit. It was never the same after that, and it was a relief to grow out of it.
Kids also take risks that adults wouldn't and need to be protected from themselves.
So we like our kids bikes to be sturdy enough to take everything that gets thrown at them, work well enough to be safe, and be durable enough to have a resale value when they've been grown out of. Unfortunately, this cuts out the cheap end of the market altogether. If you want cheap toys, you're going to have to go elsewhere.
For younger kids, we love the Puky (we say it 'Pookie') range. They come from Germany, and are fab. From two years old, we recommend the CAT tricycles.
They have a low centre of gravity, so are very stable, and can be pedaled with very little effort. They have a tipper bucket at the back, and a hand brake. Best for parents, the handle at the back allows you to push the trike along without bending over, so you can move at your pace not theirs! You can set the pedals to freewheel, so that they can rest their feet on them while you do the work. They start from £49, and we'll trade it in for the next model up when it's too small.
Once they get to 3 – 5 years, we have the 12" wheeled bicycle with stabilisers. From 4 to 7, they should fit on a 16" wheel bicycle. Both have a low centre of gravity for extra stability. Talk to Barnaby for some top tips on how to teach kids to ride without stabilisers.