Sounds like my old Festiva. My guesser isn't what it once was, but I'd say I paid about $700 back in '98, and drove it for almost 3 years. When I got it, it went "clunk" on shifts when I ran it up through the gears. It turns out the Korean steel wasn't up to northeast road salt, and the front frame was missing under the radiator. The motor mount was a front-to back bar, and the front was lying on a transverse torsion bar. When I accelerated, the engine would lift up, and then drop back down to the bar when I stepped on the clutch. A piece of old bed frame bolted under the suspension nuts gave the motor mount a new home.
I didn't break the crank, what killed mine was losing a wheel bearing. All the metal balls fell out of one of the front wheels when I was driving on the Thruway in a snowstorm. I couldn't afford the "authorized service," so I ground along 10 miles to the next exit. Going only 20-35 MPH in six inches of unplowed snow did not look all that unusual. I couldn't find a place to leave it in the city during the storm, so I drove another 20 noisy miles on local roads to dump it in my driveway.
I was looking for a Metro to replace it, or its brother, the Suzuki Swift. Then I had an opportunity to buy an '02 Hyundai Accent new. I got 34 MPG highway if I took it easy, and 32 MPG if I was driving "affirmatively" (Route 128 style). For an economy car, I wish the mileage were better, but the ride was deluxe. I had the 1600 cc hatchback with air conditioning, clock and better seats, the 1500 cc basic model discontinued after '02 had a taller rear end and probably got better mileage. I can't say bad about the Accent except no cruise control, and the steering is responsive so you can't not watch the road if your hand is on the wheel. People think it's squirrelly, but after about 3000 miles I realized it was responding properly to unconscious steering wheel inputs that other cars ignore.
If I needed another commuter tomorrow, I would probably be shopping off the same list as you. A used Prius would be nice, but I would check if the battery pack was due for replacement. I would jump at the chance for an early Honda Insight, with people getting 60-70+ MPG. Those who have them aren't selling.