Yes, unfortunately, I understand when you have to replace a car due to the repairs being almost as much as replacing the car itself. It's an easier choice if you can't do the repairs yourself - I had to make a similar judgement on my first Vibe (297,000), where I could _do_ most of the repairs, but I couldn't justify the time, as I can't ever be certain of enough uninterrupted time to do major repairs.
My wife's friend just had two places quote her $5,000 to replace the head gasket and radiator in her 2009 Toyota Corolla. Same engine as our Vibes (1.8L). Frankly, they're all trying to cheat her, as it shouldn't be more than a $1,800 job. (15 hours at $75 per hour, plus $200 for parts, plus some overhead)