I bought mine at Metro Sound. I think I paid $110 or $120 for two of them. Can't remember for sure.
I was surprised it was that expensive, but I didn't exactly know where else to get them and couldn't be arsed to search around downtown. I am sure you could get them cheaper elsewhere, but I don't know of where. I got the impression I was being ripped off.
My suggestion would be metro sound but you can also try any of the record shops along yonge. They are all pretty close to each other now. Traxx usually has some stock and so does Play De. Try and get a price idea from the net and that way you will know what you should be paying for.