If your supermarket saving efforts are limited to Sunday supplements and scissors, you’re not clipping as much off the food bills as you could be.

That’s the word from Stephanie Nelson, aka the Coupon Mom. The Atlanta frugalista says skilled shoppers strategize, seek out, surf and “stack” discount offers for the very best deals. (Stacking is a method of using more than one coupon on a single item.)

Even though September’s National Coupon Month is coming to a close, it is always a good time for consumers to get savvy about saving money, especially on food bills, which eat up a big part of the monthly budget. According to ShopSmart, a Consumer Reports publication, 94 percent of people use coupons on food, household products and health and beauty items, up from 86 percent in 2006.

Learning a few techniques, says Nelson, can double your savings.

First off, there’s more than one kind of coupon and more than one place to find them. Along with manufacturers’ offerings, there are retailer or “store” coupons (check grocery and big-box store advertisements), coupons on the back of register receipts, on store shelves, in magazines and newspapers and on product packaging. Some libraries offer informal coupon swaps: You bring in coupons you don’t need and take ones that you do. If your weekend circulars have good offerings, buy multiple copies of the paper.

Although it’s illegal to print your own money, you can do the next-best thing: Print coupons from your computer. More than 40 million people are downloading discounts, up 20 percent from last year, according to a report from the Simmons Market Research Bureau.

At Coupons.com, TheCoupon Clippers.com, RedPlum.com, Coolsavings.com, valpak.com, wow-coupons.com and Nelson’s site, CouponMom.com, visitors can print coupons for grocery items, services, restaurant offers, local retailers and rebates. (Some Web sites require you to download software or register your e-mail address to print offers.) Many newspapers offer a changing mix of printable coupons on their Web sites. Even social networking sites — like Facebook and Twitter — offer coupons (search for the company or product from the home page).

Once you’ve amassed your coupons, check out store policies.

“Check to see if they double or even triple coupons,” Nelson said. “Find out if they accept competitors’ coupons.”

Next, to paraphrase Kenny Rogers, know when to hold and when to fold.

“The average life span of a coupon is two to three months, so don’t just run out and use the coupon as soon as you get it,” Nelson said. “Wait until the item is on sale to get the very best price.”

That’s how people like Nelson get stuff for free. Her personal best, she says, was $100 worth of groceries for 25 cents. Savings like these, says Nelson, distinguish varsity-level couponers from the average user.

“Some people are paying $4 for a box of cereal, while others are paying $1,” Nelson said. “Which one do you want to be?”

Let technology be your savings guide

More coupon tips from ShopSmart magazine:

• Sign up for e-mail alerts: Go to manufacturers’ Web sites and sign up for e-mail lists to receive coupons and other special offers. (Tip: Use a separate e-mail address to cut down on spam. Sign up for a free account at Hotmail or Gmail.)

• Take along your printout: To redeem an Internet coupon, print the page (URL included) and take it with you to the store in case there is a question about its authenticity.

• Search online circulars: Before you plan menus and decide where to shop that week, scan store circulars at Mygrocerydeals.com and Sundaysaver.com, or on the sites of local supermarkets.

• Check out new electronic coupon programs: Some supermarkets allow you to select desired coupons online so you do not have to clip and bring them in store. Other supermarkets have handheld scanners that let you tally discounts and keep a running total as you shop.

• Try CardStar: iPhone users tired of carrying a wallet full of grocery and pharmacy rewards cards can try the free application that lets you load all your reward cards into your iPhone. At checkout, you just click the CardStar icon, select the merchant from your saved list and show the screen. The cashier can scan the bar code from the phone.

Some online coupon sites

• Coupons.com

• TheCouponClippers.com

• RedPlum.com

• Coolsavings.com

• valpak.com

• wow-coupons.com

• CouponMom.com

Note: Some Web sites require you to download software or register your e-mail address to print offers.