Amazon currently has the Black & Decker VEC1086BBD Smart Battery 6/4/2 Amp Battery Charger for $30.14 and it qualifies for free shipping. It’s doesn’t fall in the “best buys of all time” category but it is handy if you don’t have one already. Trust us, you want one of these before you need it.
I had a lovely time coping with a dead battery this weekend, small-child-playing-with-dome-light related, and used my very old battery charger to get the battery charged. As I was setting the battery charger up at night, in the semi-darkness I got a bit paranoid about hooking the wrong polarity up as well as leaving it charging for too long. The B&D charger has circuitry that they claim prevents both of those situations. This isn’t a power pack, and it doesn’t jump start a car (and chargers like that are available for not much more) but it does seem like a basic useful battery charger.