I would highly recommend you check out the National Center for Home food preservation, http://www.uga.edu/nchfp/
I believe I read there that pressure cookers do not work for canning. And if you're canning stock, you don't want to mess with that.
It is ok to can tomatoes without pressure as long as you add acid - they have the recipe there.
I have no problem messing around with high-acid stuff, jams and jellies, but I really wouldn't mess with low acid stuff. So I say get the pressure canner.
I believe I read there that pressure cookers do not work for canning. And if you're canning stock, you don't want to mess with that.
It is ok to can tomatoes without pressure as long as you add acid - they have the recipe there.
I have no problem messing around with high-acid stuff, jams and jellies, but I really wouldn't mess with low acid stuff. So I say get the pressure canner.