Well, don't buy them here and drag them to wherever you're going.
Just get detergent when you get there. Or bring one or two but don't bother hauling around more than that. (I like using foreign stuff, it's all part of the adventure for me and the cost is pretty much the same anyway.
Basically, they're solid tabs in separate packages. They're sold right next to regular detergent and they're considerably more pricey.