Cheapest most reliable vets in toronto for spaying?

Spay/neuter clinics at rescue centers, SPCAs and humane societies will cost you a lot less and they are often the best choice because the vets there do so many of them, they are well-practiced at it. I don't know where you are in Ontario (other than near Toronto), but here is a list of shelters in Ontario. Call the ones closest to you and they can refer you.