1. Door Hinge Adjustment: If the door is misaligned or not closing properly due to worn-out hinges, you may be able to fix the problem by adjusting or replacing the hinges. This can be a cost-effective solution, and a mechanic can do it relatively quickly.
2. Door Latch Mechanism: The door latch mechanism may be broken or worn out, preventing the door from closing securely. Replacing the latch mechanism can be a relatively inexpensive fix.
3. Door Lock Actuator: If the door lock actuator is faulty, it can cause the door not to close properly. Replacing the actuator can be more expensive than other repair options, but it's still likely to be less costly than replacing the entire door.
4. Door Alignment: If the door is not aligned properly with the frame of the car, it may not close correctly. A qualified mechanic can adjust the alignment of the door to ensure it closes smoothly.
Get estimates from several reputable auto repair shops for each of these repair options. By comparing the costs, you can decide which option suits your budget and needs best. Since your Saturn has high mileage and is relatively old, it's important to consider the overall condition of the vehicle and weigh the repair cost against its current value before making a decision.