Whenever you read the fine print on a sweepstakes promotion, or hear it read quickly during a commercial, the terms “no purchase required” might stand out. While it might sound like an easy way to get a chance to win something without spending a dime, it’s a little bit more complicated than walking into a fast food restaurant and demanding a game piece.

For example: Consumerist reader Robbie was interested in a Call of Duty promotional sweepstakes Carl’s Jr. is running right now, so he asked for a game piece at his local restaurant in California. Despite a display that read “No purchase necessary,” he said his request was denied, and that he was told he’d have to buy a cup to get a game piece.

That sounds an awful lot like a purchase, which Robbie thought might put the sweepstakes in violation of California law (and many other similar state laws in the U.S.), which says only the state can run lotteries. Basically, businesses legally can’t make you pay to enter a sweepstakes:

“Consumers often confuse sweepstakes, lotteries and contests. The main difference between a sweepstakes and a lottery is that the lottery participants have paid or promised to pay value for the chance to win the prize. The main differences between a sweepstakes and a contest are that the contest participants must use at least some skill to win the prize and must pay some value to participate in the contest.”

But because such sweepstakes often include game pieces on cups or other food containers that customers then peel off, restaurants like Carl’s Jr. understandably don’t want to just give those items away. Instead, sweepstakes like this one will include information in the rules on how players can get a game piece without paying for anything — besides postage.

From Carl’s Jr.’s rules [PDF]:

“To receive a free peel-off label with food offer or prize and unique 9-digit potential prize code without making a purchase, send a self-addressed stamped envelope (VT and WA residents may omit self- addressed postage but must include self-addressed envelope) to Carl’s Jr.® Call of Duty®: Black Ops III Instant Win Game & Sweepstakes, P.O. Box 809004, Houston, TX 77280-9921. The mail in request must be postmarked by December 16, 2015 and received by December 23, 2015.”

This same sort of situation could apply to products you buy in the store as well — think about promotions that reveal prize codes underneath soda caps, that can then be plugged in online to find out if they’re winners. Would you ask a store to give you the bottle cap without purchasing the soda? No, so just get those stamped, self-addressed letters ready if you want to participate.

For example, this under-the-cap sweepstakes from Sprite in 2014, where the rules state there are two ways for people to win — either by buying a specific soda and checking the cap, or by visiting a special promotional site, logging into your account, and requesting a code. No purchase — but you have to be willing to sign up — and therefore share your information — with Sprite.

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