Get a phone book and start calling the realestate people. I know there are a ton of places in ME if you have the change. Lake front is cheaper than ocean front yet more crowded. The further north you look the cheaper it is.
My wife is from Lubec, ME and we're there visiting often. Its the most easterly point in the U.S. Small ranches with an acre or two can be had for slightly over $100k. Not much for activities there though. The water is too cold to swim in in the summer. As you go south from there figure on adding $10k per 25 miles. Greater Portland area ocean fronts are 1/2 Mill plus.
Lake front is nice because the water always warms so you can enjoy it. My parents live on Little Sebago Lake and lounge around on the deck, fish all year round, water ski, jet ski, cruise drinking beer, ect. The in thing to do is buy a summer place, update it so you can live there all year round, sell it tripleing your money! Good Luck