(MONEY Magazine) – YOU COULD SPEND THOUSANDS OF DOLLARS ON investment research materials to boost your knowledge. But why do that when there are exceptional sources of investment information for free (or nearly free)? Yes, the public library is one terrific resource. But there are many others. Here are our favorites:

At the library. Of course, any public library has shelves of books on investing, from Peter Lynch's stock-buying Baedeker, One Up on Wall Street, to this magazine's new 579-page bible, The Money Book of Personal Finance (Warner Books, $24.95). These days, even the smallest public library system usually has at least one branch that carries standard investment resources like The Value Line Investment Survey, Standard & Poor's Stock Reports and Morningstar Mutual Funds, which otherwise sell for as much as $570 a year.

Value Line, a weekly publication, provides a wealth of information on about 1,700 public companies. You'll find a summary of each firm's business operations and key financial figures, its historical stock performance in chart form and a rating for the stock's safety and timeliness, which means the probability of share-price increases within the next six to 12 months. Value Line also covers more than 2,000 mutual funds in a biweekly sister service. The S&P Stock Reports is updated quarterly and provides two pages apiece of all the financial information you need to know on more than 4,700 stocks. Morningstar is the encyclopedia of choice for fund investors. It tracks more than 2,000 funds, with a page on each that tells you about the fund's management team, performance relative to competitors, fees and riskiness.

Call your local library to see which branch carries those publications. Also, find out which branch is considered the "business" library. When you visit it, you'll probably be able to comb through company annual reports and computer databases that steer you to recent news on a particular company.

Through your computer. Most library systems now also have a "public access catalogue" line that you can tap into from your home computer, if you have a modem. Your cost? In most cases, only the price of a local phone call.

Of the three major on-line services--America Online, CompuServe and Prodigy--we think CompuServe ($9.95 a month for up to five hours of use and $2.95 an hour thereafter; 800-336-6823) has the best stuff for investors. And that's not just because Money controls CompuServe's personal-finance site. Through CompuServe, you can chat with other stock market investors in the National Association of Investors Corporation forum (GO NAIC). You also can get 15-minute-delayed stock quotes (GO BASICQUOTES) and look up any publicly traded company's ticker symbol. GO FUNDWATCH will let you sort through more than 5,000 mutual funds based on their past performance, fees and objective and get a list of the top 10 holdings in each fund. In addition, if you don't mind paying a small fee for some of CompuServe's surcharged services, you can hook into resources like Company Analyzer, which lets you read corporate annual reports.

We especially like the Internet Investor Network (http://networth.galt.com), which is available through any of the major on-line services or via Web browsers. Here you can read the full text of about 15 financial newsletters and access most of the financial databases found at your library. Also, you can download prospectuses from at least 30 fund families including Benham, Scudder and Twentieth Century.

From the government. Finally, there's one free government publication we strongly recommend you get by mail if you're thinking about buying Treasuries. (All right, you do have to spend 32¢ on a stamp to request the booklet.) Buying Treasury Securities from the Federal Reserve Bank of Richmond (Public Services Dept., P.O. Box 27622, Richmond, Va. 23261; 804-697-8000) tells you all you need to know about buying Treasury bills, notes and bonds.

So start building your financial knowledge and your nest egg without spending more than pocket change.

The authors write the newsletter Straight Talk on Your Money ($75 a year; 800-777-2002), co-host a daily personal-finance call-in show on the WOR Radio Network and are regular contributors to CBS This Morning.