By Susan Tompor / Detroit Free PressMuch-awaited stimulus cash will begin flooding into millions of bank accounts next week in the first wave of payouts to shore up the nation's wallets.Millions of taxpayers will begin receiving the extra money to pay rent, groceries and other bills next week, or possibly as early as Thursday or Friday, some say.The first group – estimated to cover 50 million to 60 million Americans – would include people who have already given their bank account information to the Internal Revenue Service.The first group also would include Social Security beneficiaries who filed federal tax returns that included direct deposit information, according to an alert put out today by U.S.