Welcome to Canada!
The Four Points is an easy walk from T3. Gets you some fresh air. Usually runs around $120 CAD. While the property has been renovated, its nothing fancy. Has a pool. If you go with this option, I strongly suggest returning to T1 for brekkie. ( I assume you don't have MR status?)
There is an publicly-accessible staff cafeteria on the ground level. Decent food, cheap.
Personally, I would consider the new Four Points Toronto Airport East. It can be uber cheap, but does require calling a shuttle. No pool. Nothing in the area (ex. Lowe's).