We gave our oldest a $100 digital when he was 3. I went to a camera store and found a digital that the lens didn't extend when it was turned on. That was my only requirement for it. Well that and it had to be better than that piece of junk fisher price digital.
He is now 7 and has taken over 1500 pics. Our oldest girl (6) has taken quite a few too. The camera has gotten to the point where it drains the batteries way too fast. Until then it was always out and they could get it without asking. Probably time to get them a new one.
It is really interesting to see the world through their eyes. He can take pics of his brother and his sisters that we can not get and they are always at their level. They have taken pics of flowers, self portraits by holding the camera as far away as they could, feet, noses, carpet, walls, legos and lincoln logs, out the window of cars, and even held the camera upside down over their head to take pics of the person in the seat behind them.
All priceless