There's many a way to get the highest interest

Rising interest rates can be bad news for the stock market, as Wall Street was reminded last week. But in the short run, at least, higher rates are good news for savers.

Americans learned this a couple of years ago when inflation was running at double-digit levels while money market mutual funds were paying 16 and 17 percent, giving people a 5 to 6 percent real return on their savings. Now, with even more places to get good yields, they're learning it again.

Even though inflation has been kept under 5 percent all year, yields of 8 to 9 percent are commonplace, and returns of 10 percent are also available. At the same time, yields on municipal bonds have been rising to the 8 and 9 percent range, giving these tax-free investments an equivalent taxable return of 13 to 18 percent, depending on the individual's tax bracket.

The latest place for high returns opened up for business Oct. 1. It's the local bank or savings-and-loan association. Thanks to the Depository Institutions Deregulation Committee, the government agency that is overseeing - and hastening - the lifting of interest rate restrictions on deposits, the banks and S&Ls can set any maturity and pay any rate they want to on time deposits of more than 31 days.

The action was intended to give greater freedom to the market by letting the banks decide how many kinds of deposits they could handle. In most cases, the result is an even greater variety of maturities and yields that can be tailored to the depositors' needs and income. In addition to the traditional CDs, there are CDs by which you design the term (68 days, for example); CDs sold at a discount (you pay about $15,000 for a $20,000 CD and in a few years receive the full $20,000); and CDs by which you can open the account and add to it as you wish later.

Now it is possible to deposit a few thousand dollars, decide when you will need it back - to make next semester's college tuition payment, for example - and negotiate the interest rate with the bank or S&L. Many institutions, however , have set fairly narrow ranges for the interest they will pay.

Of course, whenever an industry is given a new arena to compete in, there can be some interesting wrinkles in the way it sells the products. Some banks, for example, are offering high ''come on'' rates to lure deposits. At Standard Federal Savings of Troy, Mich., you can get 13 percent by purchasing a one-year certificate for $2,500. That nice rate, however, is only paid for the first month; for the rest of the year, you get 10 percent. This is still not a bad return, as long as you read the fine print in the ad and know what you're getting.

You can, of course, get a better return if you are willing to leave your money in the bank longer. An ad for Cardinal Federal Savings of Cleveland invites you to ''lock in'' 12 percent for 10 years. The account works two ways: The 12 percent is indeed locked in, but so is the money. You should be sure any money deposited in this type of account won't be needed for some time. This type is aimed at people opening individual retirement accounts (IRAs).

At First Chicago, depositors are presented a menu under the headline ''The longer the term the more you earn.'' Interest rates range from 8.8 percent for 31 days to 11 percent for 31/2 years. All except the 31-day certificate have a minimum deposit of $1,000; that one requires $2,500. With compounding, the effective yield is slightly higher, but many banks are only compounding on an annual basis, not quarterly or monthly, which can reduce your return.

Not only are there many different rates in this new world of deregulated deposits, but the size of those deposits can also vary. One bank, for instance, may require a $2,500 deposit to get a 10 percent rate; another may ask for only

The new regulations, or the lack of them, have brought in new ways of earning competitive interest rates, but they have also brought back something old: the toaster, or more specifically, the premium. As if a wide variety of rates wasn't enough, many banks and S&Ls are giving away toasters, dishes, clocks, television sets, radios, and videocassette recorders to attract money. If you withdraw the money before you're supposed to, however, the bank will subtract the value of the premium from your account. And because the value of the premium is usually based on its full retail price, that could be a hefty deduction if you needed your money early. If it's a radio or TV you want, there's probably a better deal at a discount department store.

While the competition for your money is heavy now, it will probably be even heavier next month. After Dec. 1, there will be no minimum-balance requirements for money market or super NOW accounts, as long as they are used as IRAs. The $2 ,500 minimum balance on non-IRA deposits will remain.

Dec. 1 to April 15 is the busiest period for opening IRAs, and if the past is any guide, it will be high season for bank ads selling these retirement vehicles. Promotions will be heavy, interest rates and terms will be various and confusing, and claims of future riches will once again abound, although there may not be as many ads promising to make you a millionaire; most banks and S&Ls have seen the folly of those deceptive (in terms of purchasing power) advertisements.

Getting through the thicket of these claims and rates will take time and effort. But it can be worthwhile if you find a good return and a term that matches your needs. You should, in fact, decide how much you can deposit and when you'll need the money back before you shop for a bank or rate.

If you would like a question considered for publication in this column, please send it to Moneywise, The Christian Science Monitor, One Norway Street, Boston, Mass. 02115. No personal replies can be given by mail or phone. References to investments are not an endorsement or recommendation by this newspaper.m