THEY COST A LOT BUT SAVE YOU A BUNDLE
Rechargeable batteries are used in cameras, remote controls, torches, etc. and although they are quite an expensive outlay together with a suitable charger, they will nevertheless save you a bundle of cash because they can be used 30 to 100 times over, depending on the brand. If you compare the cost of 100 penlight batteries with the cost of 1 rechargeable battery, you will start to see the savings. They come in various sizes: penlight , torch batteries, square 9V types and others as well.
AN EXAMPLE OF SAVINGS
Usually a set of 4 rechargeable penlight batteries (size AA) with an included charger, will cost about 10 times what a pack of 4 non-rechargeable AA batteries cost.