Throughout the shopping years, a contestant would buy some jewelry or other sort of too-expensive-for-what-it-is item and the plug would start:
"With your [insert Gucci/Tiffany/etc] gift certificate, you can select this [prize in question]..."
...before continuing with a descrip. of the prize and its retail value, which was subsequently the value of the gift certificate. There were even extra wheel prizes that used the same idea; despite the wedge reading whatever the item being described was, they were awarded a gift certificate.
If I had to guess, I'd say it was the show admitting the items were overpriced junk and offering the contestant a chance to merely select it specifcally from that manufacturer. Does anyone know the reason for certain?
-Jason