What do you use for battery holders?
I'm just wondering what people use to hold batteries in battery-powered projects. In my first attempt I used the holder from one of those bike lights that I'd accidentally broken the mounting piece off of, but I don't generally break them very frequently. I've also seen battery holders for sale at hardware stores, but I found them a bit pricey (converted, nearly USD 3,- for a piece of plastic). So what do you use if you need something to hold batteries that you have to be able to replace?