The New Year will be kind to the smaller saver. Starting Jan. 1, the size of the minimum deposit will decline on several types of high-interest bank and S&L accounts. The happy result: Many small savers will have a chance to earn more on their money.

Three types of accounts are affected: The money-market account, which pays market interest rates on savings (current average yield, 9 percent); the Super NOW account, which pays market interest rates on checking deposits (current range, around 7 to 8 percent), and all time deposits with maturities between seven and 31 days.

Right now, you need a minimum balance of $2,500 to get these accounts. After the first of the year, the minimum drops to $1,000. Deposits under $1,000 will continue to get the passbook rate of 5.5 percent (or 5.25 percent in the Super NOW account).

Banks don't have to lower their minimums if they don't want to, and some probably won't. Others may try a step-rate system, linking the size of your interest rate to the size of your deposit. But wherever there's banking competition, savers should be getting a better break.

In 1986, the government will completely deregulate all these accounts, as well as the passbook accounts. If they want to, the banks will then be able to pay high rates to even the smallest saver.

But as banking customers have learned to their cost, high interest rates aren't a gift from Santa Claus. To pay those rates, banks and S&Ls are charging customers for a wide range of services that they used to deliver free.

If you deducted all your new bank fees -- for all manner of services -- from the interest you earn on all your accounts, the net profit you earn from your savings and NOW accounts would be less than you think. In fact, you may not be getting very much more than you did in the bad old days whan savings-account interest rates were regulated.

One piece of evidence is a study by Herb Taylor, an economist with the Federal Reserve Bank in Philadelphia. He has shown that bank accounts that look very different and pay different rates of interest can actually be yielding the same return, when certain hidden benefits are taken into account.

For example, NOW accounts pay 5.21 interest on your checking deposits while regular accounts pay nothing. But both accounts deliver some amount of "implicit," or unseen, interest payments, in the form of services that the bank doesn't charge you for. This might include gifts for opening an account, free monthly statements and below-cost processing charges. The more you use your checking account, the greater the value of any below-cost services that you get.

Taylor found that zero-interest, regular checking delivers a lot of below-cost services. As a result, he says, these accounts yielded an implicit interest rate of around 6.4 percent in 1982, after deducting the service charges you pay. In the same year, NOW accounts paid an effective rate of 7.1 percent (counting both cash interest and implicit interest). So the two accounts are not very far apart.

In straight dollars and cents, the banks are charging higher fees for zero-interest accounts, while customer charges on NOW accounts have remained relatively low, Taylor told my associate, Virginia Wilson. The average customer charge on a NOW account was $10.90 in 1982, compared with an average charge of $35.51 on a zero-interest checking account.

Why does zero-interest, regular checking show such a high yield in Taylor's study? It's because customers keep low balances in these accounts, while the value of the below-cost services is high -- hence, the implicit interest rate also is high.

This doesn't mean that it hardly matters which type of checking account you choose. "Implicit" interest is an economist's game for measuring the total value of a banking service. But you can't spend implicit interest. As a banking customer, you have to compare the dollar cost of an account to the interest earned, to see what serves you best.

Even after fees, NOW accounts pay a real return in cash interest. And you need those real returns to help pay all the other charges associated with modern banking.

When the minimum deposit moves down to $1,000 in January, it's a buy.