how much is it worth?

[pianistimo]

a 1987 pontiac bonneville with over 300,000 miles.  still runs.  passed smog inspections.  has good tires and engine and battery.  blue book says zero, but we're donating the car to a charity which may either salvage the car or run it for a few more months.  i told my husband that a cab would be worth $250. for a month or two of the driving.  is this ok thinking or should i actually calculate the car only on blue book?  is torp around?  how do you calculate donation values of things? 

[musik_man]

If it runs well, I'd think it'd be worth something.  I drive a '83 BMW 745 which we bought for $800 w/o emmisions testing. 

[pianistimo]

that's what i thought.  i'd hate to donate it for zero if there is some intrinsic driving value (say the emissions passing).