I visited Starbucks this morning, as I do often, and prepared to order my “usual” skinny mocha latte. Today, though, my purchase decision was disrupted by a barista passing out free samples of their new Frapuccino flavor. It was delicious, and I decided to forego my usual latte for one. The impact of sampling or “try before you buy” is not new to the retail world, but today, companies like Birchbox and Trunkclub are taking it to the next level by leveraging....