One of the main expenses I find, with my children's toys are batteries. I find that so many toys seem to need powering these days, compared to when I was small, it can bve quite irritating. I tend to make sure that I give batteries with a toy that needs one, so that it can be played iwth straight away. However, the toys we have at home often need new ones.
The solution in our family has been to give the children some rechargeable batteries aa. They have a charger and know how to use it and so whether they need to power their cameras, hot wheels or remote control car, they are able to make sure that they have some batteries available. The charging will cost me in electricity of course, but it is a lot cheaper than having to pay for new batteries all of the time. I have tried buying cheap brands and they can seem to be flat when you buy them, so getting rechargeable seems to be the obvious solution. It is also a greener solution as well, which is always good.