You can spend hours online or on the phone putting together the various elements of a ski vacation. Or you can opt for one-stop shopping and contact a specialized ski tour operator for your airfare, lodging, transfers and lift tickets. They don’t charge a fee, and they often offer wholesale airfare, typically lower than most published fares. Is it really cheaper to buy a package than to assemble your vacation à la carte? Usually. But do the math and decide for yourself.