i need help! just bought my friends 91 hatchback it seems to have a problem with the alternator. runs fine but after a while the battery drains completley before i spend money for an alternator wat other problem may it be??

 

Could be either a bad battery or alternator. Drive the car to AutoZone where free of charge they will evaluate both the battery and alternator. Before doing this, however, you might want to clean the battery terminals and connectors to ensure that they are making good electrical contact.