Boston — OK, you have decided the new individual retirement accounts (IRA) are a good idea. They save on taxes. They can offer a firm savings program. You can now put aside up to $2,000 a year, even if you are already covered by your company's retirement program.
But where should you invest your IRA money?
There are banks, savings-and-loan associations, brokerage houses, mutual funds, insurance companies, and credit unions - all putting on an advertising blitz to pull in as large a share of these accounts as they can. Much of the money going into IRAs now is probably ''old'' money simply being shifted from one account to another. Some is ''new'' savings that will help fill financial institution coffers.
The accompanying table shows the six main financial institutions that are competing for the 40 to 60 million potential IRA customers. The listed products, interest rates, and restrictions for each category are, of necessity, very general. So, wherever you shop for an IRA, here are some possibly useful questions:
* What is the interest rate? How is it calculated? How often is it compounded? Is the rate guaranteed for a specific length of time?
* What is the minimum initial investment? What is the minimum on subsequent investments?
* Are there charges to open the account? If so, is this a flat fee or is it a percentage of the deposit?
* Can I contribute to the IRA through payroll deduction?
* Are there any annual charges?
* Are there any charges to transfer money from one of your accounts to another account, as from a money fund account to a bond fund?
* What are withdrawal penalties if you want to take your money somewhere else?
Here are a few additional points to consider:
* Your first investment decision need not be your final one. Many institutions have little or no charge for transferring or withdrawing your money. The law permits you to shift your IRA account once a year to another investment vehicle. You must make the shift within 60 days after withdrawing from the first IRA.
Federally insured depository institutions, such as banks, savings-and-loans, and credit unions, probably offer the safest IRA vehicles, particularly for people who don't want to to be tending their account. The 18- to 30-month certificates offered by banks and S&Ls are paying, according to their ads, from 12 to 15 percent interest at maturity.
* Put money into your IRA account as quickly as you can. If you can afford it , put the entire $2,000 in now and and start collecting interest immediately. The effect of compounding - especially if it is done daily -- means the sooner the money goes into the IRA, the more it will earn.
* Don't get hung up on the $2,000 figure. Many people are saying, ''I can't afford to put $2,000 a year in an IRA.'' They should put in what they can afford. Even if it is only $500 (less than $10 a week), that's $500 that is not taxed by Uncle Sam this year and will probably be taxed at a lower rate at retirement.
The IRA accounts: who has what? Institution Investment Interest Minimum Initial Annual Withdrawal choice rate (1982) investment charges charges penalties Banks Certificates: 11 to 15 $100 to None None 6 months 18-month variable percent $1,000 interest 18-month fixed 30-month variable 5-year fixed Savings- Certificates and 7 to 14 None to None None 6 months and-loans passbooks, 18-to percent $500 interest 30-month variable or fixed rates Mutual Money Market fund 11 to 15 None to None, $3 to None funds Growth stock fund percent $1,000 usually $15 Bond fund Income fund Growth stocks Brokerages Self-directed Unknown None to 5% to None, butNone mutual funds $1,000 $25, some fromt commis load sions Credit Share 10 to 14 None None None None, to unions accounts percent 3 months' interest Ubsyrabce fixed annuities, 12 to 14 $15 to None to None 7%, drops companies mutual funds percent $600 8.75% to none