Done right it costs less, alot less. The sacrifice is mostly time, and trips under 15-20 miles in many cities thats almost a tie during the morning or afternoon rush in many cases. Also depends on YOU, some bikers are hardier than others, some faster, some slower. Some can haul big loads, some cant. Some have issues with traffic, some dont. Trying to handle a family with small kids could be a problem, but I know some that do it. Where there's a will there's a way. People lived car free for centuries, why would now be any different?