The phrase "full cart" means that your shopping cart is completely filled with items or that you have bought everything you needed.
Sentences with «full cart»
I love all of the things listed and now have a very full cart in Amazon. (dessertfortwo.com)
Working in this role means that you will be performing a lot of physical work, including pushing and pulling empty and full carts from one place to another, gathering all carts and placing them in their specific areas, cleaning and maintaining carts and hand baskets, providing assistance to baggers, and even assisting customers in locating their choice of items. (coverlettersandresume.com)
After attempting this experiment for a month and failing many times (what would YOU have done at the grocery checkout with four kids and a full cart only to realize you forgot cash??) (businessinsider.com)