Need some cheap travel advice!!!?

I live in the Columbus Ohio area and am looking at going on a trip sometime this summer, between now and umm.. maybe mid Sept. Im wanting to keep the price under $450. Maybe some where on the water, or a city with lots of stuff to do (not New York). Anyone know any good sites, I have already looked into Expedia, Orbitz, and Travelocity. Also any great unknown of cities would be cool too, as long as there are things to do, outdoors, shopping, etc. THanks so much!!!

Portsmouth, New Hampshire. There is a new plane service from Columbus to Pease starting at 10 bucks. Skybus.com. Right across the river is a shoppers paradise in Kittery, Maine. You can go up to Portland as well.