Wrong wrong wrong. All the answers above are wrong. You don't have to pay more for disposal. Why? Because disposal fees for old tires are already charged to you when you bought the new tires. Canadian government always charges disposal fees to new tires so you do not dump the old tires anywhere to avoid paying that.
Take it to any Canadian Tire or Wal-Mart and they will dispose it for you with no charge. The Wal-Mart near my house even has a huge bin outside for people to dump used tires so you don't need to go inside the store. Do not try to dump it anywhere else because it's bad for environment.