Summer’s here and it’s the season for young scammers to start making their neighborhood rounds. In central Ohio, a charmer calling himself James Williams falsely claimed to be raising money for new uniforms for his high school football team. He collected not only cash at the houses he visited but also the names and phone numbers of his victims.

In West Virginia, a salesman sold coupon books offering discounts at area businesses to benefit a youth achievement program at an area college. At $5 each, they seemed to be a great deal. Unfortunately, the coupons—like his story—were bogus.

But the most common scheme is a summer classic: door-to-door deceivers selling subscriptions for magazines that never arrive.

Since May 2008, the Better Business Bureau has received some 1,100 complaints from consumers in 46 states and the District of Columbia about student-age scammers selling magazines door to door.

This season is expected to be a banner year for these young con artists, who often bilk their victims of hundreds of dollars.

“The sales reps might claim to be a neighborhood youth trying to raise money for charity, a school trip, or even for troops in Iraq,” explains BBB spokeswoman Alison Southwick. “The victim pays with a check on the spot, but the magazines never arrive.” Neither do any refunds requested from the 50 companies employing those sales crews.

What’s more, your signed check provides the dupers with your bank account and routing number. Or, if you don’t use fraud-preventing gel ink pens, cellophane tape can be placed over the front and back of your signature and the check can be “washed” with acetone to remove everything else you’ve written—leaving a blank, signed check that can be used to steal more of your money.

Practice these defensive strategies:

• Don’t buy. Whenever strangers come knocking, don’t buy their stories or their products. Prices of magazine subscriptions sold door to door, for instance, are often marked up about 300 percent. If you really want a magazine, ask the salesman for an order form and investigate the company at the Better Business Bureau’s website.

Although rip-off vendors often change their names, some to avoid include Trinity Public Relations and Seedtime Publications in South Carolina, Prestige Sales in Arizona, Omni Horizons in Indiana, True Visions in Virginia, Greater res Inc. in Memphis, Tenn., and Seattle-based Fresh Start Opportunities. All have generated dozens to hundreds of complaints and have an “F” rating with the BBB.

• Cancel quickly. If you make a purchase at your door or elsewhere and want to cancel it, act quickly: The Federal Trade Commission dictates a three-day cancellation allowance for a full refund on purchases over $25. (Legitimate salesmen must reveal this rule during their pitch; if they don’t, assume it’s a scam.) If you have a receipt, the company must provide a refund within 10 days of receiving your mailed cancellation notice. Report violators to the FTC, the BBB and your state attorney general.

• Close the door. Never allow a hot and sweaty “sales rep” into your home. “While the resident is in the kitchen getting them a glass of water, often the solicitor is stealing their medication, checkbooks and wallets,” says Phil Ellenbecker, who runs a website that tracks door-to-door scams and other crimes. So far this decade, at least 300 felonies—including rape and murder—have been committed by traveling sales crews against residents and fellow crew members.

Sid Kirchheimer is the author of "Scam-Proof Your Life" (AARP Books/Sterling).