If you go on vacation in the northeast you'll find that it's much, much cheaper to cook your own lobster than buying it at a restaurant. That's particularly true this past year (2012) and this year (2013) because the price of lobster in Maine is down and you can find it for as little as $3.50 a pound.
Of course you'll have to be staying somewhere with a kitchen and you'll find that a lot of the time it's cheaper to rent a house than stay in a hotel for a week. Rent a house or stay in a bed and breakfast. In a pinch stay in a hotel with kitchenettes, but sometimes they don't have a lot of cookware so you'll have to bring your own. Most cottages, cabins, and house rentals will have a stockpile of pots and pans from the owners and left by previous renters. Previous renters often leave a decent selection of spices as well, but you'll still need to bring some of your own or pick some up at the nearest market.