It's virtually impossible to answer that question without knowing the condition & model of the vehicle (mechanical & cosmetic), number of miles, etc. Is your car a 4dr, 2dr, station wagon, or ???? Is it low mileage with pristine, original paint or has it lived its' life through the commuter wars? Prices can vary greatly from area to area and depend on "curb appeal" (color, etc.), as well as salesmanship.
For a "ball-park" figure, the 'Old Cars Price Guide' (12/2004 edit.) lists '69 Caprices from $1400 #5 condition (4d, 9p Station Wagon) to $16,500 for a 2dr Custom Coupe in #1 condition. Quite a spread !

-Bob