The Kia Soul almost seems like it was born for rideshare use: Boxy, utilitarian, cheap, but durable -- and you might even find one in taxi yellow. If you're also enticed by that Kia or Hyundai 10 year and 100,000 mile warranty on the powertrain, know that it's probably voided by rideshare use of the car, at least following a strict reading of the documents.
The Goldilocks car: Not too common, not too ritzy. Qualifies you to handle premium rides, but should cost only $7,000 to $8,000 more than a nicely trimmed Toyota Camry of similar vintage.
I know, rolling in this wasn't what you dreamed of back in the halcyon days of your youth, but a Grand Caravan can qualify you to take higher earning rides and may actually cost less than a late model used sedan of similar vintage. Remember, a large vehicle can always handle a small ride, but the reverse is not true.
Toyota Prius might be the all around rideshare champ: Sky-high miles per gallon in town and on the open road, tough as nails and a turning radius nearly 7 feet tighter than a Camry, making it effortless to pull an irritating U-turn right in front of the rest of us.
Along with Toyota Camry, Honda Accord and Hyundai Sonata, the Fusion presents a little better than a Prius and has skosh more room (though a Prius has a very useful liftback cargo area). And most of the mainstream sedans like Fusion can he had as hybrids. The other win: Sedans are so unpopular with car buyers right now you can probably get one easily, but your customers won't care if you're driving a car that's out of fashion as long as they are comfortable in the back.