Laura and Robert Bellavia have two overriding financial concerns -- college and marriage.

The Windham, N.H. couple's daughters are young -- Gianna is 7, Tessa 5 and Layni 4 -- so, fortunately, Laura and Robert won't have to start cutting checks for any weddings for quite some time.

The cost of college is another matter -- one that the Bellavias are addressing now. For the past three years the family has been saving $300 a month in a 529 college-savings plan. To date, the account is worth some $10,300. Video: The best option?

"When I had my first daughter, I looked up how much college would cost -- I was shocked," says Laura. "It scared me, and I knew that I had to do something. Even now I hope that we can step it up even more."

It's unlikely the Bellavias will be able to cover all the costs for three college educations. But Morristown, N.J., financial adviser Jody D'Agostini says the family is definitely on the right track in taking a significant bite out of the overall expense. Chart: How student debt has soared

"There's a lot of opportunity for them to save a great deal of money that grows tax free with a 529," says D'Agostini. "There's really no other savings vehicle that

even comes close." Reality check: 529 pros and cons

The Bellavias certainly aren't alone in their commitment to 529s. Projections from Financial Research Corp. of Boston estimate assets in 529 savings plans will top $250 billion by 2011. That's way up from about $1 billion in 1998. Video: It's not for everyone

For those unfamiliar with the term, 529 saving plans (named after section 529 of the tax code) actually come in two forms: prepaid tuition plans and college-savings plans. Some state plans offer versions of both.

Prepaid tuition plans are a form of contract: They allow you to prepay future tuition costs at current prices. Just how much you pay depends on the age of your child and the state in which your future collegian will be educated. In Florida, for instance, $35,740 locks in a four-year university contract for an eighth-grader. Those same four years at the University of Florida would likely cost roughly $45,000 for an in-state student four years from now.

Many state-sponsored prepaid plans require a commitment to large state institutions. Another option is the Independent 529 plan, which lets you prepay tuition and apply it to some 240 member colleges and universities -- mostly smaller, independent schools.

There are drawbacks to prepaid arrangements.

For one thing, only a small number of states offer them. Additionally, some mandate a residency requirement to participate; other states don't offer full backing in the event the plan runs into financial problems. Also, depending on how old your kid is and which plan you're interested in, you may have to come up with a fair chunk of change to buy in.

By far the more popular 529 option is the savings program. The basic function is simple: you choose the plan that you like (all states and the District of Columbia offer them with a variety of features and options), name your beneficiary and set it up with a modest amount of paperwork. Then, start cutting the checks.

The savings 529 is advantageous on several levels.

First: As the donor, you have complete control. You decide when to make deposits and withdrawals and which investment option within a particular plan to choose. With few exceptions, the named beneficiary has no rights to the funds. That makes them financial-aid friendly; it also eliminates some of the problems involved in Uniform Gift to Minors accounts, where the child eventually takes ownership of the funds. (In some cases, that can mean a Porsche instead of Princeton.)

You also get terrific income-tax breaks with all 529 plans. Your investment grows tax-deferred, and distributions to pay for your child's college costs come out free of federal tax. Your own state may offer some tax breaks as well.

Look, too, for program matches. For instance, Colorado has a dollar-for-dollar match of up to $500 in contributions for lower- to middle-income residents.

In general, 529s are also a breeze to maintain. Since the accounts are professionally managed, there's nothing for you to do except ensure that the deposits keep flowing in.

Lastly, they're generous. Many states allow you to deposit more than $300,000 into a single account.

Not that the process is problem-free. One problem is that there are so many 529s from which to choose, each with different features and benefits. (Some, for instance, invest in mutual funds, while others opt for more conservative certificates of deposit.)

Nor are they always the best choice for your situation. Withdrawals from a 529 may be subject to a 10% penalty on earnings if the money is used for something other than college costs. So only buy into 529s if you're

committed to using the money for college.

There are other concerns.

Deborah Fox, of Fox College Funding in San Diego, points out that many have unduly high operating expenses -- costs that are passed on to investors. Moreover, they can be inflexible. For instance, plans with several investment options often limit how often funds may be readjusted in a given year.

In fact, Fox points out that one purported advantage to some 529s -- automatically adjusting the portfolio mix to become more conservative as a student nears college age -- may actually work against the child's best interests.

"For instance, when we had the last severe market correction, account owners could not prevent the 529 plan from selling off equities to reallocate to a higher percentage of cash or income securities," says Fox. "They were selling equities at the worst possible time -- at a market low."

Other caveats: Paying an entire college bill with 529s can disqualify you from Hope and Lifetime Learning tax credits for education expenses. If you have money left over in a 529 after college bills have come and

gone, you'll pay a 10% penalty to get the money out.

Here are six other shopping tips:

1. While many 529s are sold directly to investors, others must be purchased via a broker. As a rule, investor-direct plans are less expensive than those involving a broker.

2. Look at the investment style of the plans to see if the plan offers mutual funds from one company or if there's a blend.

3. See if buying into a 529 in the state where you live confers any tax advantages.

4. See how well the plan has performed in the past (but bear in mind that 529s have only been around for a few years at most).

5. Check fees and other costs associated with the plan.

6. Lastly, investigate specific features. Check whether the plan allows contributions from other family members.

Also, if it appeals, see if the plan automatically adjusts its portfolio mix (more aggressive when kids are younger, less so as they approach college age), and make sure you're comfortable with that aspect of the deal.

Produced by Elizabeth Daza/Graphics by Hakan Isik and Joe Farro