Merrill Lynch allows 30 commission free trades per month.
To qualify for up to 30 $0 online equity and ETF trades per calendar month, you have to meet any one of the following criteria:
Total combined balances of $25,000 or more in your Bank of America, N.A. deposit accounts: Checking, Savings, FDIC-insured CDs, FDIC-insured IRAs
Or, total combined balances of $25,000 or more in cash balances in your Merrill Edge self-directed account(s): Bank Deposit Accounts sweep option with your Cash Management Account® (CMA®) or Retirement Assets Savings Program II (RASP II) sweep with your IRA