Wandering somewhat from the topic:
They're way cheaper than having something built, and because they're meant to withstand severe weather on the deck of a ship, they're watertight and sturdy.
Google turned up several pages of listings of places that sell in New Hampshire. I think this is the one my friend bought from:
http://www.aranbox.com/containers_for_sale_nh.html This is their list of uses:
Storage:
Landscaping, agricultural, livestock supplies
Paint, chemicals, tires, hazardous materials
Recreational field sports equipment
Files, books, business records
Tools, equipment, tack supplies
Furniture, appliances, auction items
Vehicles of all shapes and sizes
Portable generators
Police/Fire/EMT/Search and Rescue (SAR)
Working Space:
Modular office or shop
Military barracks or command center
Guard shack
Mobile field office
Communications shelter or command van
Welding shop or sandblasting booth
Concession stand
Hunting shelter
Driveway or portable storage unit