If you start with a small front wheel drive car that is sound in body, but bad in engine, use a new controller, run 72 volts, use an 8-10 HP, DC, fork lift motor,and GEL batteries, you should be able to do it for a little over $2K.
25 miles is easier to do at 45mph than 55mph.
I did my Yugo for 1K. The batteries will be the most costly part.
Make your own adapter plate and coupler. Sell off as much of the removed parts as possible. Radiator and heater core etc, for scrap.
Install new brakes, use the original stick shift trans, spare tire is optional as is the jack. keep the interior, but remove rear seat, make your own cable ends, buy a good charger.
Shop swap meets, hamfests (for electronic supplies), wrecking yards, etc.
Build with safety in mind. Finish off all modifications, so they look good.
Low cost doesn't have to look crappy.
Then enjoy your EV smile....