Many families believe they just can't get by on a single income. Consider some evidence from the 2002 census: Out of 19.6 million married couples with children under 12, only about 5.3 million parents -- 5.2 million moms and 105,000 dads -- stayed at home to care for the kids. Yet in a parenting study done for Warner Books last year, 87% of the mothers surveyed said that they would stay at home to raise their children if they could afford to do so.

"This is an all-too-common dilemma," says Sheri Iannetta Cupo, a certified financial planner with Sage Advisory Group in Morristown , N.J. Here are five tips to make at-home parenting work.

1. See what you'll save. "The first thing that I realized was there were a lot of hidden costs to working," says Jonni McCoy, 45 years old, who 13 years ago decided to quit her job as a senior buyer for Apple Computer to stay at home with her then-three-year-old son. Though her family lived in the expensive San Francisco Bay area and she was bringing home 55% of the joint income, it wasn't so hard: "A tremendous [amount] of expenses just disappeared."

The biggest saving was day-care expense. Also gone were the career-wardrobe and dry-cleaning bills, along with the almost daily deli and restaurant tabs. Gasoline and parking costs also dropped now that she didn't commute, and her car-insurance premium went down because she switched from commuter to leisure status, which automatically lowers rates in most large metropolitan areas. Plus, the couple's tax bill fell significantly.

"I've met people who [net] less than they [bring home] because of all these expenses, and they've never thought about it," says Mrs. McCoy, who in her spare time runs a Web site for stay-at-home parents (MiserlyMoms.com).

2. Shrink your budget. It seems impossible, with a newborn baby. But it's not. Most people don't have much control over the electric bill, "but the discretionary money that passes through your hands, you've got some control over," says Denise Topolnicki, a stay-at-home mom and author of "How to Raise a Family on Less than Two Incomes." Most stay-at-home parents find they can significantly cut the grocery budget now that they can spend more time at the supermarket. Others say that with a baby at home, they eat out and go to the movies less often.

3. Eliminate debt. The smartest thing you can do to prepare for at-home parenthood is to plan it all far in advance. Get rid of credit-card debt first. It's costly.

4. Have a safety net. With only one breadwinner, the family should start an emergency fund -- at least six months of living costs in an easy-to-tap account such as a money-market fund. Another way to avoid a financial crunch is to set up a home-equity line of credit. If you never use that line of credit, there's no interest charge. If you do use it, Mrs. Cupo says, "the bank will start to charge you interest based on what you've written the checks for." Don't confuse this with a home-equity loan, where you get the cash (and start incurring interest) right away.

5. Tweak insurance, savings. Adjust your life-insurance policies now that the family depends financially on one parent. Insurance experts recommend coverage equal to at least five to seven years' worth of the working spouse's income. And insurer State Farm puts the "value" of a stay-at-home spouse at up to $70,000 a year when you factor in child care, chauffeuring and so on. Fortunately, term-life insurance is inexpensive for people in their 30s in good health.

Save less, rather than nothing, toward retirement -- if you must pare your 401(k), at least contribute enough to get your company match. Save for the kids' college, but not at the expense of neglecting your retirement. There are means of getting through college -- "loans and financial aid -- but there's nothing like that to help you through retirement," Mrs. Cupo says.

And don't forget: Uncle Sam gives some tax breaks to parents.