Watch out for this advertising trap

Often, when a store advertises several items at a certain sale price—say, three pineapples for $6—you'll still save proportionately if you buy just one. So for instance, that single pineapple will cost you $2, as it should unless the sign or ad says otherwise. And that's the problem. When the sign lists conditions, they can be easy to miss, as I discovered not once, but twice at my local supermarket.

First, it was Ajax dishwashing liquid. The sign said three for $5. At $1.67 each, that's a 23 percent savings off an already-discounted price of $2.19. It wasn't until I got home that I noticed on the receipt that the single bottle I'd purchased was rung up at $2.19. So I dragged myself back to the supermarket and saw that the sign said that I had to buy three to get the savings. I returned the bottle I had purchased and bought another three to get my discount. I had learned my lesson, or so I thought.

But I fell for the same thing about a week later when I grabbed a box of Cheerios from a stack with a sign in front of it promising three 18-ounce packages for $7.47, or $2.49 a box. While I was enjoying my Cheerios breakfast the next morning, I suddenly had a troubling thought. I dropped my spoon into my bowl and went to check my receipt. Sure enough, I had paid $3.69 for my Cheerios, 60 cents more than I'd expected. I despondently returned to my soggy bowl of cereal. Back later at the supermarket, I checked the sign. There, in small print, were the words: "MUST PURCHASE 3 TO RECEIVE DISCOUNT."

Check out our Supermarket Buying Guide for more advice on saving at the supermarket, including additional traps and tricks to be on guard against and supermarket rating (for subscribers).

I wondered: Were there others who were right then washing their dishes with Ajax or slurping Cheerios while experiencing the mistaken satisfaction that they had gotten a deal?

Sure, I could have gone to the customer service desk a second time and presented my case for a why I needed yet another redo, this time for the Cheerios purchase. I could have complained about how unfair and maybe even deceptive it is to disclose offer details in such small print. Normally I would have, and I'm not exactly sure why I didn't this time. Maybe I just didn't want three boxes of Cheerios. Or maybe I was more disappointed in myself for being repeatedly trapped by this little advertising gotcha than I was mad at the store for perpetrating it. I decided to accept that 60-cent overpayment as a way of shocking myself back into astuteness, my 60-cent anti-sucker disincentive!

But one thing I can tell you for sure. From now on, I'll be scrutinizing those signs. I'll be on guard for that tricky, infuriating fine print, whatever it is. And I'll be complaining to the manager if I see it. I hope you will, too.

—Anthony Giorgianni