On a trip to Boston last month, I was determined not to buy anything I didn't need. Translation: I was determined not to buy anything at all.

But then, in Banana Republic, I came across a deal too good to pass up.

The shoe section was brimming with marked-down shoes, including one pair, Kamea, I particularly liked. It appears other shoppers did not like Kamea quite as much (or that the Banana Republic merchandise buyer grossly overestimated the number of size 9 feet that would be walking in the door).

Kamea had started off her retail life priced at $98. The little trail of sale tags on the box told a sad story: First the shoes were marked down to $69.99. Then $44.99. Then $31.97, the "final sale" price on the day I saw them.

But it turned out that $31.97 wasn't the final price. There was also a sign that read "40 percent off all final sale items." I did the math: that would bring the shoes down to under $20.

I have a Banana Republic card (see * below) that earns rewards points for each dollar I spend. And I just happened to have a rewards voucher for $20.

I brought the shoes to the sales counter. I told the clerk I was pretty sure I wouldn't have to pay anything for them. She looked at me skeptically, then rang them in.

Free shoes for me!

* My Banana Republic card (good at Gap, Old Navy and Piperlime, too) is the only store brand charge card I have, by the way. Lots of store charge cards also means lots of payment due dates to keep track of. For me, that was not a good thing.