Uses a battery pack that converts the kinetic energy of electrons released from a stimulated vespomide cell into electrical power, in a miniaturised take on an aneutronic reactor (more or less complete energy conversion). Vespomide is an element that has more or less replaced every conventional form of power production in this universe, since it's clean, efficient and offers sufficient power. Powers anything from wristwatches (with nano batteries) to cities and starships.
This vehicle could operate continuously for up to a month before the pack fuel cell needs to be swapped out. That is if you were running everything on it for that month.
Not much . If you built it today, it would be quite a bit more. In the time this is set, materials and tech considered expensive today are far cheaper and more readily available, so the unit cost drops.