Come on rookie! You can fit more than that in there.
I never fear a trip to Cotco, & I love the looks I get when I roll up to the Boxster with my cart full of TP, paper towels, case of water, case of yogurt, laundry detergent and other assorted items.
My biggest haul to date, a new vacuum cleaner (in the front seat), a 14-piece cookware set (in the frunk) and a few things in the trunk. Love this car!