RUN away. Don't walk. The 1998-2000 W202 C-Class was a good selling car, and there is no shortage of good examples. If the required repairs were inexpensive, the seller would have had them done prior to selling the car. Something smells REALLY bad here. Even if you get the car for $10K, I would be willing to bet real money that you'll end up more than $15K out fo pocket before it's sorted out.
All IMHO, of course...
1998 C230 "Black Betty"