Buy it.
If I were you I would buy the car, it sounds like a good deal, especially since your buying it from a friend. RL's run forever, your daughter would get well over 150,000 miles out of a 99 RL. I would go with it over any GM car, especially a Malibu as I have heard they are P.O.S. after a few years. Check out Consumer Reports to get some reliability ratings on the cars your looking into, by the way they recommend all RL's as used cars.
If I were you I would buy the car, it sounds like a good deal, especially since your buying it from a friend. RL's run forever, your daughter would get well over 150,000 miles out of a 99 RL. I would go with it over any GM car, especially a Malibu as I have heard they are P.O.S. after a few years. Check out Consumer Reports to get some reliability ratings on the cars your looking into, by the way they recommend all RL's as used cars.