Hi,
So sorry for what happen to your dog.
I do not know of a discount place, but
Brimley-Lawrence Animal Clinic in Scarborough is a little cheaper that most other vet. There main vet, the one that those the surgery is very good.
For the other vets doing routine check,shots etc, they are only good for basic and sometime I feel like I know more about dogs that them
I also recently start going to
Green Lane Animal Hospital in Thornhill ON. They aren't specially cheap but I think they are really fair. The lady is so nice, she explain very well (and I always have A LOT of questions ) and I found her very competent.
Also, if you know of someone like 1-2 out of town that know a good vet. Everything is $$$ downtown so the drive might be worth it for you.
Good luck.