I have been slowly and slyly converting all of our family's batteries over to rechargeable, over the past year.
Yes, they most definitely cost more at the time - but it's that long term benefit that I can see that makes me do it.
It's about $30NZ to get 4 rechargeable batteries. But the benefits are that far less toxic batteries are generated (by far my only reason for doing it).
However, there is a great financial blessing when you switch over to rechargeable batteries - as well as an ease of stress when using digital cameras...however "cheap" you get them, you don't have to buy batteries any more, which feels great.
Personally, I just enjoy the absence of guilt.
This is our family's personal battery stash from before switching to rechargeable in the photo above - I had been collecting and saving for a very long time, waiting to turn them in to the city's hazardous waste pickup locations (like that's going to happen). You can also turn these in to your local "transfer station", and they will dispose of them properly for you.
I recently found a way to replace Shane's trusty big ole flashlight (photo below above on the left). They don't make rechargeable batteries that size. The bulb was broken by one of the kids. I went to the auto parts store to look for another. I found they don't even sell this type of flashlight anymore - the same brand one is made with an LED now. So I bought a very affordable ($15) flashlight that runs on 3 x AA batteries, and has heaps of LEDS on it on the side, and on the end - it's very bright. It's supposedly for fixing cars. Works for me. Look at the difference in the waste it would generate in 2 years (give or take).