Two 16 inch wheel bikes that grow - $150
We got these two bikes new for our twin girls when they were 4ish. They rode with the training wheels for almost a season but soon outgrew the training wheels and were riding without them.
We installed rear wheel hand brakes to get them used to them while still having the back up of the pedal brake. As opposed to buying the next size up, we then got new longer seat posts, because they outgrew the ones that came with the bikes. The next size up (20" wheels") just did not fit right. They were too big and it was going to shake their confidence. They had outgrown the posts, not the bikes. They are 7 1/2 years old and super confident riders with their new geared mountain bikes on trails.
These little bikes are used but in great shape. I'm a bike fanatic myself and paid close attention to bike fit. These bikes will allow your children to develop competence and confidence with a bike size that is not intimidating and will last many years.
Pickup in Williamsburg, Brooklyn. We would prefer to sell them both at once but the bikes are available individually for $75 as well.