Welcome to Grand Slam Storage Center – St. Louis, MO: Need Storage? Our state of the art storage facility has the perfect solution! Grand Slam Storage Center in St. Louis has a wide range of sizes and both climate controlled and standard units. One of our most popular features – DRIVE THRU ACCESS – protecting you and your stuff from rain, wind and snow while loading and unloading. We also have RV and vehicle storage, Budget truck rentals, boxes and packing supplies and easy payment options. Access to your storage unit 7 days a week.