What Buses go from Buffalo airport to Toronto?

The cheapest option I know of is to take a metro bus (204 is preferable but 24 will work if you don't mind a longer trip and having to walk a few blocks in downtown buffalo) to the Greyhound Bus Terminal. From there, you can take a Greyhound bus (or possibly Coach Canada) to Toronto. You can do this for under $20 if you're lucky. Various alternatives include using a taxi instead of a bus. If you'd rather not go to downtown buffalo and are willing to pay at least $50 not to, there are some shuttles that run from Buffalo-Niagara Airport to Niagara Falls, Canada. From there, you'll need to find another shuttle/bus to get back to Toronto. I don't know of any direct routes, except taxi services, which will be really expensive (maybe up to $300).