The biggest issue may be that it isan eleven year old car. I had a 99 Buick Regal and the only issue I had was AC problems at around 85K miles. I was told that it was unusual to have issues with the AC. The car had a 3800 SC engine which got decent milage using hitest. I had a tune up at 60K miles (100K spark plug change must be an advertising ploy) and new brakes around 50K, tires and battery were replaced.
The 3800 engines have been around a long time and are quite reliable. But at 11 years old, and what kind of mileage on the clock it is hard to say if it is a good deal for what price. It shouldn't be more than a couple of grand tops.
My 99 got traded in back in '06 with a little over 100K and was worth about $3k. It was a nice riding car.