I ride such a bike, and I would no longer call it cheap - the range/speed is limited enough that I feel compelled to have a car anyway that just sits. I still have to pay taxes and insurance on that car, plus the yearly oil change (at least it is paid for). What with replacing the bike tires, chain, and cassette a lot more often than I expected I end up spending as much on bike maintenance and I would on gas and the other costs of the car are paid either way. If I could get rid of the car it would be cheaper, but otherwise no.

don't get me wrong - I encourage everyone to ride a bike where they can. However it is for health reasons not saving money.