The Cash-and-carry policy replaced the neutrality act. Before cash-and-carry, arms sales from the U.S. were limited to nations that were not current belligerents in a conflict, i.e., those who were not actively fighting a war. To allow Britain to obtain weapons without, however, giving up the appearance of neutrality, the cash-and-carry policy was born. Any nation could obtain weapons in the U.S., as long as it paid for it before delivery ("cash") and transported it from U.S. ports on its own transportation ("carry"). Although this way, Germany could have potentially purchased weapons, too, in the U.S., the reality of Britain's relationship with Canada and Britain's control of the Oceans made it highly improbable/implausible/impractical that Germany could buy weapons in the U.S. for World War II. "Neutrality" thus having been maintained, Britain could begin to obtain massive amounts of war materiel in the U.S.
So, to answer the question in short: Before cash-and-carry, the U.S. also got cash for weapons, it just could not sell them to nations that were already in an active war.