Transmission went out at 90,000 miles (2001). However, it was due to my ignorance of the car's design. Unlike most other cars, this model Prizm has a differential reservoir that fills from the underside only, separate from the transmission reservoir itself. The seal around my Constant Velocity shafts, where they enter the differential, was leaking. I regularly checked my transmission fluid levels (from above), seemed fine, thought nothing of it. Apparently, the differential drained dry, so my transmission seized up on the highway. I hadn't noticed because the clicking sound that preceded it for a couple weeks sounded like Constant Velocity shafts going bad, so I replaced them (as the boots on those were broken). Fortunately, a friendly fellow from Detroit stopped within minutes and we returned home safely.
Constant Velocity Shafts replaced at 90,000 (2001).
Muffler replaced at 110,000, in 2002.
Starter went bad at 120,000, in 2004.
Water pump at 120,000, in 2004, which dripped onto my timing belt and ruined it.
All the above were original manufacturer parts, which is pretty amazing when you think about it, especially the muffler. Was able to perform most all work myself, except the water pump. Unfortunately, the engine must be removed to do this.
Never had a problem finding after-market parts at major auto parts stores.
All in all, it sounds worse than it was. Being already 10 years old when I bought it, it had been passed around and some maintainance neglected, but I only paid $2000 for it, so I feel I got my money's worth in four years of everyday use.
Love the way it drives. Wife has a 2000 Prizm and we both prefer my old 1991 version. I think the larger body, on the same size wheel base, makes for less responsive handling.
Also, the forward-peripheral visibility is better in my car. Sometimes cross traffic is obscured by the windshield framing in her car, but not mine.
Will be getting rid of this one, probably junkyard, and buying a 2001 or 2002 model for sure.