If that charger is what it appears to be, a box that holds 4 AA's, then it is overpriced by 200% or more. I can even get you as many links as you wish for $10 or under, in several countries. Or the Radio Shack part #'s to make your own. Heck I even made one from a plastic Q-tip box, and I've still got the Q-tips!
Don't get me wrong, it is a good idea. And should charge your battery at least once even with inferior batteries, probably 2-3 times.
Also don't believe the FAQ on that site re the 1.5 vs 1.2 volt thing. Alkalines start at 1.5, but then drop consistently until dead, giving much less than 1.5v on average. NIMH (or NiCad) start at 1.2 or higher, but maintain an AVERAGE voltage close to 1.2 until nearly empty, when they fall off very quickly. Plus alkalines are throwaway, and are more expensive in the long run.