If you want a rebate, you’ll have to file a tax return.

That was the official word yesterday from the Internal Revenue Service.

I mentioned this point in passing in Saturday’s MoneyLine, noting that it wasn’t official.

Now it is.

It’s not a big deal if you’ve already filed a return, or you plan to file later this year.

But it is big news for the millions of people who do not ordinarily file tax returns because their income is so low.

This category includes lots of seniors whose main source of income — or only source of income — is Social Security or certain types of veterans benefits.

If you’re in that category — whether you live in your own house, in an apartment or in government-subsidized housing — you may not have filed a return in a number of years.

But now know this: You won’t receive a rebate automatically; you’ll have to file a federal income-tax return first.

You won’t have to actually pay any tax. But by filing a return, you’ll give the IRS the information it needs to issue you a rebate — such as your name, address, Social Security number and the amount of your income for 2007.

Remember that you generally need at least $3,000 of “qualifying income” for 2007 to be eligible for a rebate — and “qualifying income” includes Social Security benefits as well as certain types of veterans benefits.

What kind of return will you have to file? The answer isn’t clear yet. IRS spokeswoman Peggy Riley said yesterday that people in this category will have to file “a simple tax return” to qualify for a rebate.

“They’re going to have to file some type of simple return. We just don’t have all the details worked out yet,” Riley said yesterday.

The IRS probably won’t issue any more information on this point until after President Bush signs the rebate legislation into law (which could happen later this week).

So maybe you’ll have to file the “short form” – Form 1040EZ. Or maybe the IRS will come up with a special form just for this purpose, as it did last year for people to claim the phone-tax rebate.

Whatever solution is found, you’ll have to file something.

The good news is that there’ll be plenty of volunteers available to help you fill out and file the required form.

And that’s important to know, because for people with limited incomes, it simply won’t make sense to pay someone to do a return that you’re filing only for information purposes, not because you have a tax liability.

You’ll be able to obtain free tax-preparation and tax-filing service through such organizations as the Volunteer Income Tax Assistance (VITA) program and the AARP Tax-Aide program, which is affiliated with AARP, a membership organization for people 50 and older.

Most volunteer sites are already up and running. To find a volunteer site near you, simply dial the United Way hotline at 211.

Or call the IRS toll-free at 1-800-829-1040. Or call the AARP Tax-Aide program toll-free at 1-888-227-7669. The program’s volunteers will be available to help you fill out and file your form, said Barbara Peters, spokeswoman for the AARP’s state office in Rhode Island. “We’re able to help,” she said.

You can also do it yourself, or have a trusted family member or friend do it for you.

Keep in mind, too, that the sooner you file your return, the faster you’ll get your rebate. If you file by the usual April 15 deadline, your rebate check will probably be among the first batches to be issued.

The IRS plans to start issuing rebates in May, Riley said, and rebates will be issued through late spring and summer.

On to the questions:

Q: I write on behalf of my mother, whose only source of income is Social Security.Under the tax rebate plan, it is my understanding that she is entitled to a rebate of $300.Your article a few days ago said it has not yet been determined if they have to file a return to be eligible for that [rebate] . . . . The IRS has two addresses, one if you owe money and one if you get a refund. If the return is for informational purposes, which address should be used?

– G.G., Warwick

A: If your mother’s informational return is filed electronically — perhaps by a volunteer organization mentioned above — you won’t have to worry.

What if she files a paper return? Where should she send it? That’s one of the issues that IRS officials will be looking at in the days ahead, Riley said.

(My bet is that she’d have to send such a return to the same address that’s used for returns that show a refund due. But we’ll have to wait a bit longer to find out for sure.)

Q: I understand that you need to have $3,000 or more earned income to get [a] $300 rebate, and you have to pay taxes to get more than $300.A married couple, over 65, retired but with self-employment income of about $5,000 will owe about $707 dollars [in] self-employment taxes.Will self-employment taxes qualify to get more than $300 for each one?

– J.M., East Providence

A: It should qualify them to receive a rebate of at least $300 apiece. But whether they’d be eligible for a higher amount isn’t clear.

The original rebate legislation said you had to have a certain amount of earned income — essentially money from a job — to be eligible for a rebate.

But the final version of the legislation that was approved by Congress — and which President Bush said he will soon sign — makes things easier in this sense:

In general, you must have at least $3,000 in “qualifying income” for 2007 to be eligible for a rebate, and “qualifying income” includes Social Security retirement, survivors and disability benefits, as well as certain types of veterans benefits.

A summary of the rebate legislation, issued by the Senate Finance Committee last week, said that “qualifying income” means “the sum of net self-employment income, veterans disability benefits (including payments to survivors of veterans), and Social Security benefits.”

Based on that definition, it seems certain that your parents will be eligible for a rebate of at least $300 apiece.

But when I put your question to Riley, she said it will be best to wait until the IRS issues more details, perhaps later this week.

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