First thing to do is to remove the blanking cover (or whatever cover is fitted in place of the cig lighter) in your car and have a look behind to see if the wires are already there. They *could* well be taped to a wiring loom nearby.
If so, all well and good. Could be a simple job of plug and play. You may well have to put a fuse in the fuse box, but the wires could already be live because of other equipment sharing the same supply.
If no wires present, then it's a bit more involved. ie, needing a switched live supply that is also fuse protected.