If you've spent any time hitting up the giant wholesalers or other markets this holiday season, you've probably figured out that you can make a full meal out of those tasty little samples they often dish out. Which seems like a good thing, for you ... and for your wallet. But a new study shows that these tempting little treats really do entice you to buy what you try ... and maybe some other stuff like it. Researchers tracked the sales in half a dozen stores that provided samples of snacks in four categories: healthy, salty, frozen, or branded by a large coffee-shop chain. They found that nothing while shopping convinces consumers to buy the featured product more often than does simply seeing the product displayed at the end of the aisle. They also found that repeating the sample offering multiple times translates into sustained interest in the product.