monthly payment can vary so greatly, that question really can't be answered. the pure model starts at ~11,500 ('09 model may increase in price slightly), but options can add up fast, like any car. and then there are two higher-priced models, again plus all the options. check out
www.smartusa.com for information on various models, factory options etc.
of course, the car can make long trips just fine. it is rated for speeds up to 90 mph, but does not have cruise control unless you have it added aftermarket. i drove mine 350 mi home from the dealer and it wasn't unpleasant at all, compared to any other vehicle.
Linear Mode
