I drive a cheap car and am a cheap person, this is what I did to reduce noise from outside:

1. Insert aquarium tubes inside the door rubber seal. Spray some silicon grease inside the tube before inserting to lubricate the insertion.

2. Spray rubberised undercoating inside the spare tyre well and inside each wheel well. I use Bondo spray (3M product) bought at Ace Hardware.

3. Bought cheap self-adhesive sound insulation foam from Ali, tampal behind plastic fenders.

So far so good!