Amazon.com sells the "BC-900" charger for $29.99. (free shipping) You can get a cheaper charger, but I don't think you can get a nicer one. All kinds of fancy features and it measures the exact mAh capacity of each battery!
I would say a good deal on these is less than $2/battery. I think the Durcell branded Sanyo batteries are the most common, but be careful - there are two versions - one with a black top made in China, one with a white top made in Japan. (same label, different battery) The one from Japan is an Eneloop. The one from China is...?