Subway will give away sandwiches next week as part of a major media campaign to mark National Sandwich Day. The Milford, Conn.-based sandwich giant will offer a buy-one-get-one deal on Nov. 3. Customers who buy a six-inch or a Footlong sub, plus a 30-ounce drink, will receive a sandwich of equal or lesser value for free. The company will introduce the promotion with an ad that will begin airing during primetime television Thursday evening.