Putting money in a box is fun for children especially when they can see their savings grow through the plastic windows on each side. These windows are removable so you can access the money when it becomes time to spend it, and they can be re attached easily with the screws, so the box can be used over and over.
Perhaps you could set a target savings level - when you reach half way then you can spend it.
For adults the Money Banks are a good place to put loose change - you'll be surprised how quickly it mounts up. Then buy yourself something nice (like one of our puzzles) as a reward.
Money Banks can also be used to keep coloured stones and pot pourri.