Charles Schwab is an undisputed industry leader in mutual fund investing. Compared with other income fund brokers, Charles Schwab offers more than 3,000 no-transaction-fee funds, allowing clients to be more active in mutual and income fund investing while keeping more money in their pockets. Clients can also choose between maintaining minimum account balances of $1,000 or making monthly auto deposits of at least $100. With that benefit, nearly anyone with a full-time job can afford to invest through Charles Schwab. And if you know someone who might like to start investing, you might want to check out the Charles Schwab referal program, which awards $100 for new first-time clients.