Being in the fitness industry I have seen the demand of these things skyrocket through the roof. At first I thought it was a "FAD", but seeing them and using them I realize these things are here to stay. To be honest I dont even think they have scratched the surface yet.
Kettlebells have replaced entire dumbbell sets, even entire home gym systems. The fact that you can target any part of your body with simple exercises has really attracted the attention of many new users, regardless of age, weight & fitness condition.
http://www.treadmillfactory.ca/ has really taken these things by the horn and started offering kettlebells at very reasonable rates! I would have to say it's probably the best pricing in Canada!
here is the link to their kettlebell page and accessory page :