Folding bicycles have as many gears as you want, from about 1 to 21, and they certainly are the perfect fit for a smaller EV. They also travel well, on buses, trains, ferries, and airplanes and almost always without any additional fee. They weigh well under 50 pounds so airlines treat them as a regular piece of baggage, even on domestic flights. Some collapsed foldables even use one wheel as a caster so you can roll it instead of having to carry it.
But back to their use in EVs; my BikeFriday Tikit (16" wheels) fits nicely in the rear hatch (also without the removable "ledge"/trunk cover), similar to the Dahon above. It has it's own integral cover for when folded and thus keeps the car clean(er). My BikeFriday Pocket 8 (20" wheels) goes into the back seat or on top of one seat when folded down. I could easily fit 5-6 BikeFridays in the Spark with the back seats down.
As for price, foldables are expensive, but largely because most have topnotch Shimano and other similar components. There are many now in the used market, though, from many different makers. You can easily find one for under $1000 US.
As for external options, especially for larger, non-folding bikes, there appear to be very few. I have yet to see a roof rack for the Spark (which would have significant extra drag), and it appears from the comments above that a hitch-mounted rack--my preferred option--is a non-starter at this point. Hatch-racks are tricky due to the Spark's fairing, and not optimal for many reasons anyway.
Stepping back a bit, I will say that even with a folding bike, it's nice to have an external rack. It keeps the car cleaner and able to hold four people, and is quicker to load/unload when using it as a "dingy." I wish someone would make or adapt a hitch mount for the Spark EV.