Whether you hire a discount or full-service broker will depend on how much help you want with your investments -- and how much you're prepared to pay. Many discount brokerage firms offer tiers of advisory services -- and each level typically has its own minimum. But the fees are generally 1 percent or less per year, depending on the amount of assets you have with the firm.

At Fidelity, for example, if you have $50,000, you can invest in model portfolios at annual fees of 0.25 percent to 1.7 percent of assets. But if you want someone to actively manage money for you, you'll need a minimum of $200,000 in assets (or $50,000 in a retirement account), and you'll pay between 0.55 percent and 1.5 percent annually, depending on how much money is in your account.

Although Vanguard is known mainly as a purveyor of low-fee mutual funds and ETFs, it does offer brokerage services as a convenience to its clients. The fund sponsor and brokerage combination also offers a full range of financial advice. It takes $500,000 in assets to become a client of Vanguard Asset Management Services. Being a VAMS client means that you have an ongoing relationship with a dedicated team of two Vanguard employees -- a financial planner and his or her associate -- who manage your investment portfolio, allocating your money to a mix of Vanguard mutual funds and ETFs, and help you with other aspects of your financial life. Annual fees range from 0.2 percent to 0.7 percent of assets. If you have $10,000, you can open an account at a full-service brokerage, such as Morgan Stanley. You'll work with a broker, who, for a fee of up to 2 percent of assets annually, will provide guidance on mutual fund investments. But to get more-comprehensive advice at Morgan Stanley -- from an adviser who offers banking services and retirement and estate planning -- you need at least $100,000. Fees are negotiable and may include commissions on investments, asset-based advisory charges or both.

There is no minimum at Edward Jones, says Danae Domian, an adviser with the St. Louis-based firm, which has 10,000 offices in the U.S., many of them one-broker shops in small communities. Charges depend on the type of investment products you buy and can include ongoing asset-based fees to manage the portfolio, as well as transaction costs or annual expenses of mutual funds. For that, clients will get advice that "spans 90 percent of their financial needs," says Domian, including paying for a child's education, preparing for retirement, generating income in retirement and estate planning.

(Nellie S. Huang is a senior associate editor at Kiplinger's Personal Finance magazine. Send your questions and comments to moneypower@kiplinger.com. And for more on this and similar money topics, visit http://www.Kiplinger.com.)