you can buy replacement blades, but for the comb I sell, which is fairly inexpensive, the blades are as much as the whole thing.
I cannot believe you have worn out a blade already, I use these combs in the salon (where they are used daily)and use them for a year or two before they dull even a little bit. you should only be using it on the very ends of the piece hair so I cannot imagine that you have worn it out already.
DebbieS.