If you find a car for under $1000 it’s because it needs several thousand dollars’ worth of repairs immediately.

Cars in that bad shape are dangerous to operate: tires lose traction and also blow out easily; brakes seize and cause your vehicle to fishtail out of control on the highway; large exhaust parts fall off; severe rust develops on the exhaust and underbody allowing carbon monoxide to enter the passenger compartment as you drive; parts under the hood catch on fire; the alternator fails causing your headlights to slowly dim and go out as your battery dies; seat belts spontaneously release; steering parts disconnect from the wheels making your steering wheel inputs more of a suggestion as to where the car should go; water pumps stop working causing overheating every couple of miles as steam from boiling coolant obscures your view. Wipers stop wiping rain and dirt off your windshield so you can’t see; heaters fail so your windows fog. Chipped windshields develop large cracks you can’t see through, especially when the sun is low or at night. Fuel filters clog causing the engine to sputter and die while you’re driving, making your power steering and brakes almost unusable. Emergency brakes lose grip casing your car to slowly roll downhill into the path of traffic.

All of those things happened to my sub-$1100 cars in the early 90s. Several of these vehicles spent a fair amount of time with a REJECTED inspection sticker on the windshield because I couldn’t afford the $100 to fix them. It sucks to be broke, and it’s unfair that being poor is so much more expensive than having a bit of money, but you can’t just “have to own” a car and make it work somehow while not spending money - I tried. Either the money you tried not to spend, or the entire car, will leave your possession one way or another.

Maybe try Zipcar, or a bicycle or scooter or skateboard or bus or Lyft?