I specificaly mention Lithium batteries (Ion or sulfide eludes me ath the moment fairly certain Ion though)
and that based on the cost of a limited production bike (and additional batteries of the same type) which uses said batteries one could build a compact car for roughly 11G.
For less power there is an even a cheaper production L-ion powered bike but it's range is 65 Mi at 65MPH....But a compact car for two with a loss of top speed and possibly range one could pull the cost below 8G.
But again one must be willing to give up a great deal of whats taken for granted in todays autos.
I am....but then my fave mode of transport amounts to an engine, trans, frame, lights, fuel tank and a seat...no radio, no heat or air conditioning, no floor, no roof, no windows
....a bare auto as described be me amounts to a cabin (likely polycarbonate or ABS on a simple tube chassis), essential lights, bare minimum wipers, bare minimum heat, small cheap tires, very basic rigid plastic seats (beach buggy style) and a bare minimum motor to push it all down the line (the unit from either of the afforementioned bikes would likely be a good candidate).
I shall seek the links and provide them when found (had em but the demise of my old computer has me screwed up at the moment as far as valued data such as this goes at the moment.)
BTW I'm not trying to argue with you merely clarify
