Watch the boats unload while you wait for your order. Hit the Local Grocery Stores
The absolute cheapest way to get lobster is to buy it straight off the boat or at a local pound.
Ask for "new shell" or soft-shell lobsters. They are harvested just after molting. Because they have less meat than hard-shell lobsters, they are significantly cheaper per pound. Plus, the meat is famously sweeter and the shells are easy to crack by hand!
Famous for massive rolls, though lines are long.
It sounds less glamorous, but Maine supermarkets often have the lowest per-pound prices in the state.
Known for fair market pricing and incredibly fresh hauls.
They will often steam them for you for free while you shop.