Of course there are cappers that cap threaded bottles. The big beer companies use them all the time! LOL!
But seriously, best case scenario is to use a bench capper. But I wouldn't. I've seen what it does to the necks and threads, and IMO it's just way better to collect the unthreaded bottles and just use them.
Here in Michigan we have a deposit law. I can go to most any store or party store and ask to dig out some clean, used craft bottles and they only cost 10 cents each. This was handy for when I first started. After that I just saved the craft bottles I bought, and reused most of my homebrew bottles.
If you don't have such a law, you can probably ask at a recycle place. They may let you take them for free. I'd be surprised if you didn't have some kind of access to pry-off bottles in that part of Canada.