How much will it cost me to do anything relating to concrete? (sidewalks, garages, basements, removing and replacing old concrete, building concrete canoes, etc.)

Concrete and labor prices vary widely from different parts of the world, and even from region to region. The best thing to do is call your local ready mix concrete supplier and ask them. They have the best handle on material and labor costs, and should be able to give you an estimate. If they can't, they can at least give you a recommendation on who could.