WASHINGTON — If you really want to make a good investment, then get the February issue of Consumer Reports.

In it you will find an informative investigation of low-cost and no-cost retirement planning services. The consumer magazine also threw in an evaluation of one high-end (i.e., high price) financial service.

There is enough free information on the Internet and in books to help people develop a well-balanced investment plan. However, many people are afraid of making a financial mistake that they won't catch for years.

So an increasing number of consumers are hiring financial planners to show them what they need to do or reassure them that they've made the right investment choices.

The question is: Do you have to pay a lot to get the best advice?

Consumer Reports found there are some good low-cost options for consumers. To test what's out there, the publication sent three employees from Consumers Union to get retirement advice from banks, mutual fund companies, online planner networks, a Web-based software service, and discount brokers. Consumer Union is the nonprofit publisher of Consumer Reports, which is an independent publication that accepts no advertising (to be as unbiased as possible).

The testers used companies that offered free plans. They also paid for retirement planning advice that was priced from $250 to $3,000.

The three testers represented a range of ages and financial needs: a 42-year-old with a stay-at-home wife and kids ages 2 and 6; a 63-year-old married granddad with grown kids, including one in college, and with his eye on early retirement; and a 48-year-old married working mother with one child in middle school.

Consumer Reports discovered that, for the most part, the testers received good, solid investment advice whether it was free, bargain-priced or expensive.

And guess what? Even with a planner — low-cost or expensive — you've got to spend a lot of time checking what they recommend, according to Consumer Reports.

One of the most useful pieces of information in the report is a caution about the assumptions that planners make.

If any of the assumptions in your plan are way off base, you might end up not investing enough or wind up overly confident that you can retire earlier than you actually can.

The following is a list prepared by Consumer Reports of common assumptions planners use and what you need to know about them, whether you use an adviser or develop your own plan: