When I see college graduates celebrating their achievement, I can’t stop wondering about all the loans many will be paying off for years to come.

But I’m also relieved that my husband and I set up 529 plans for our children.

This is why I’m celebrating 529 College Savings Day on May 29 (get it, 5/29?). The best thing is, I don’t have to buy a greeting card.

Nevertheless, I was surprised to learn that most people aren’t aware of this vehicle to save for college, even those who are likely to have the income to make this investment. For the past three years, the financial firm Edward Jones has commissioned a survey to gauge what Americans know about 529 plans (named after Section 529 of the Internal Revenue Code).

In 2012, 37 percent of respondents correctly identified a 529 plan from among four potential options. Some thought it was a retirement account, a form of life insurance or a low-cost health-care plan.

Only 30 percent of survey participants could correctly identify what a 529 plan is about, and the awareness is dropping. Among those with a household income between $50,000 and $75,000, awareness was only marginally better at 32 percent. The awareness level increased when income increased, but it still wasn’t as high as it should be. Forty-two percent of households with income between $75,000 and $100,000 could identify a 529 plan, and 48 percent of Americans making more than $100,000 answered correctly.

Here’s how the prepaid and savings plans work. The advantage to the 529 plans is that its earnings are not taxed if the funds are used to pay for qualified college expenses. In most cases, earnings are also free from state and local taxes. There are no income limitations on who can contribute to an account. And I particularly like this feature — the account owner controls the money.

A prepaid tuition plan allows you to pay a child’s tuition in advance. The point is to lock in for tomorrow at today’s rate. However, be careful about funding a prepaid plan and thinking you are done. It covers only tuition and fees. What if your child wants or needs to live on campus? Room and board alone can be as much as tuition.

In the 529 savings plan, which is the most popular, you invest much as you would in a workplace 401(k). This means your returns are based on how your portfolio performs throughout the years. Most 529 savings plans offer age-based options in which the investments become more conservative as the beneficiary gets closer to college age. This is what we have selected for our children.

All 50 states and the District of Columbia offer at least one 529 plan. Although the 529s are state-sponsored, you can invest in any of them regardless of where you live. Many states offer a tax deduction for residents who use their state’s plan.

Start your research about 529 plans by going to the one run by your state. Two Web sites that provide good information are savingforcollege.com and collegesavings.org, which is run by the College Savings Plans Network.

On savingforcollege.com, you’ll find a quarterly analysis of the best and worst 529 plans based on short-term and long-term investment performance. If you have questions about 529 plans, register for a live one-hour webcast hosted by savingforcollege.com. at 1 p.m. Eastern time May 29.

Many state 529 plans are having promotional contests. The College Savings Plans of Maryland is offering a chance for one child to win a $529 Maryland College Investment Plan account and to become “Zookeeper for a Day” along with a free family membership to the Maryland Zoo in Baltimore.

On savingforcollege.com, you can find a list of 529 Day promotions. In Virginia, accounts opened between May 15 and May 29 will be entered into a drawing to receive a $2,500 contribution.

“The issue gets more notice when there are a bunch of promotions, contests and other hoopla focused on one single day,” said Joseph Hurley, founder of savingforcollege.com.

When it came time to pay for my daughter’s tuition, fees, books, and room and board each semester, I simply made a telephone call. It took less than 10 minutes to process the payments to her school.

Each time, the customer representative ended the call by asking, “Is there anything else I can do for you?”

“Nope,” I said, breathing a big sigh of relief.

Readers may write to Michelle Singletary at The Washington Post, 1150 15th St. NW, Washington, D.C. 20071 or at michelle.singletary@washpost.com. Follow her on Twitter (@SingletaryM) or Facebook (www.facebook.com/MichelleSingletary). To read previous Color of Money columns, go to postbusiness.com.