If you have a garage, go the the Dollar store and buy the cheapest plastic trash can AND garbage bags that fit it. Make it a HABIT to throw away trash from your car. You could start with making this a Saturday chore. After awhile you start to like it cleaner and you will clean it out more often. I LOVE LOVE LOVE to burn paper so I pick up any paper trash and take it to my burn barrel plastic trash can that is inside the door close to the washer and dryer, where we also clean out the dryer vent. It is lightweight and I can wheel it out to my burn pile.
This makes the cleaning a lot more fun than a chore.
You can also buy a small trash can, aGAIN with bags that fit for aluminum. You don't get much for recycling, but I started doing this before my DD's left home. They swill down lots more soda than me, but I gave them my "cans can", with the label written on the lid, and they deposit aluminum cans AND beer tops in it faithfully, and I take the bags in to recycle when I can do it.
Also, I have a 2 story house and I put things on the stairs under the railings that need to go upstairs. I take them up on my trips to the 2nd floor.
These tasks are 5 minute jobs. I reward myself when I do them and although I don't think I will EVER have as neat as place as
@ninnymary , my house and car are a LOT cleaner than they used to be AND I am finding things all of the time that I don't have to buy again.
Back to your original question, I do transport gardening supplies in my car, but when the items are big, I use my truck.