this may sound overly simple but when I need something for my bike or any of my cars, I check amazon.
Gives a good indication of the range of prices that are out there, and I know what Im looking at more or less.
Then finding a good supplier is the next step.
The only exception for this was tires for my VS650 - I ended up googling tires and got them from Bike Bandit.
This must work both ways across the border. The best deal I found for rotors and brake pads for my car was from a Canadian supplier - Max Pads.