Instructions
eBay
Set up an account on eBay. Make sure you have a credit card on file so you can purchase items.
Type "stormtrooper army" into the search bar. Browse the options for individual armor pieces or entire suits.
Look for accessories such as blasters, helmet speakers or voice amplifiers. These pieces enhance the authenticity and creativity of your costume.
Bid early and wisely to avoid losing out on items you need.
Stormtrooper Shop
Register an account with UK-based retailer Stormtrooper Shop. Enter a login name, email address and password to sign up. Make sure you have logged in before browsing and purchasing items.
Click the link titled "Stormtrooper Costumes" at the top of the left-hand menu. These are full-sized costumes. Select the size you need.
Click "Add to Basket" to select items. Enter your credit card information to finalize your purchase or continue browsing to buy more items.
Click the "Stormtrooper Armour Parts" link at the bottom of the left-hand menu. Browse the offerings for individual armor parts you need.
Official Star Wars Costumes
Visit the Official Star War Costumes site. There's no need for an account.
Browse the left-hand menu and click the "Stormtrooper Costume" link. Look for the Supreme Stormtrooper Costume option -- the only costume that comes with molded armor parts.
Click the "Add to Cart" link. Follow the directions to enter your credit card information.
Local Retailers
Visit your local costume or hobby store. Ask about authentic Stormtrooper costumes or armor parts.
Visit other stores if you can't find what you need at one location. Ask the retail clerks if he knows of any specialty stores or hobbyists that sell authentic armor.
Browse Craigslist or other sites to locate retailers or craftsmen in your area that make or sell authentic Stormtrooper costumes.