I just bought insurance for two cars last week and asked about the price difference if just insuring one vehicle. It was less then $30 a month difference to have both vehicles insured vs just the Z. I didn't buy comprehensive/collision on the DD as a $500 deductible exceeds the value of the car! :)
My DD is a 1992 Chevrolet Lumina w/ 260,xxx miles. I paid $400 for the car and it's actually comfortable to drive w/AC and it's been reliable.