You could try Priceline.com where you choose your city, your type of accommodation and your dates. You then choose a price limit, say $80/night or $100/night.
The only glitch is that you have to take what you get. I've used the service with good results. THe other thing to remember is the B&B system.. Here in Toronto there are an extensive number of B&Bs - see
I travelled through Quebec and Ontario a few years ago by hire car. We just stopped at a motel in the early evening wherever we happened to find ourselves. We stayed in Montreal, Peterborough, Toronto, St. Catherine's etc. There are so many motels that you always fnd a reasonable one for a good price. I know prices have gone up but I'm sure motels are still a good option. Have fun!