A shopping cart basket comprises one or more modular baskets couplable to a bottom basket having a plurality of wheels extending downwardly to allow the shopping cart basket to roll. Each of the modular baskets has a foldable bottom wall that can act as a bottom of a separate basket or can be folded against a side wall of the modular basket. The modular baskets could be used to hold items within a smaller compartment, and can be combined with the bottom basket to form a roll-able shopping cart having a larger compartment. Such a cart is advantageously used in a store, such as a grocery store, a retail shopping mall, or a home improvement store.