One suggestion I'd make so that you don't have to worry about batteries is to do what I do: I use rechargeable batteries that last a long time. Your best bet for those is to go to Batteries Plus. They may cost a bit at the outset, but they also come initially with a charger (at least how I got them) and I always have some extras available to switch out while I charge some, which is what I did at GaFilk.