Not so fast. What seems like the best offer might not be, once you look hard at each part of the package. Here's how to compare aid:

Get past the summary. Most financial-aid offers have a friendly-looking summary page that lists the school's total cost, total amount of your aid package and your family's contribution. Be warned: Focusing exclusively on this section could cost you thousands of dollars.

A typical aid offer consists of two main parts: gift aid and self-help. Gift aid is basically grants and scholarships -- money that needn't be repaid. It may include a federal Pell grant, a federal Supplemental Educational Opportunity Grant (SEOG), state grants and money from the school. The self-help part includes subsidized loans (Perkins loans, subsidized Stafford loans) and work-study programs.

Watch out for letters that list Parent Loans for Undergraduate Students (PLUS) and unsubsidized Stafford loans as part of the aid package, cautions Kalman Chany, president of Campus Consultants in New York and author of "Paying for College Without Going Broke." These are non-need-based loans that any student or parent can take out, and shouldn't be considered part of need-based aid. "With some schools, it may seem like they're giving you a package for 100% of the money, but they're just giving you loans you could get anyway," he says. That's not to say the PLUS and unsubsidized Stafford loans aren't beneficial: Their interest rates are much lower than those on a private loan.

Also, make sure the school's attendance cost includes books, transportation and personal expenses in addition to tuition, fees, room and board. If one or more of these isn't in the total, add it to your out-of-pocket costs (or family contribution) for that school in order to compare all packages fairly.

Compare apples to apples. What really matters is how much you're expected to pay and how much the student must borrow. To figure this out, break down each offer into three categories: net cost of attendance (total cost of the school minus any scholarships, grants and work-study); out-of-pocket costs (expected family contribution plus unmet need, including any PLUS loans if listed in the offer); and need-based debt (need-based loans your kid must get).

What looked like the biggest aid package might be the one that leaves your kid with the most debt. Or the private college you thought was too costly may have offered enough grants to make it more affordable than a public school.

"Schools that have larger endowments, like Princeton or Harvard, tend to be more generous with the grants," says Mike Kantrowitz, publisher of FinAid.org, a Web financial-aid resource.

Try for more. The offer you get isn't a final verdict. But schools don't negotiate like car dealerships. To request an aid review, there must be something in your family finances that changed lately, that you expect to change or that sets your family apart. Maybe you overestimated your income or tax bill when filling in the form.

To get a successful review, write a letter to the school describing your unusual circumstances, and provide independent documentation, says Mr. Kantrowitz. If mom was laid off a few months ago, attach a notice from her employer. If possible, visit the school. "When the school sees that you've taken time out of your life to meet with them in person, it makes a significant impact," says Carl Buck, vice president of financial aid for Peterson's, the education-publishing unit of Thomson Corp.

Don't get complacent. What's offered one year might not be the next. Federal aid is based on a family's income from the prior year. And if the school offers your child a merit-based scholarship for two or more years, make sure the kid will work to keep it, or you might find the tuition bills soaring.