Richard Thalheimer's company RichardSolo was one of the pioneers of the iPhone backup battery business. Way back in 2008, the company came out with the RS001 1800 mAh backup battery, at a price of US$69.95. Well, if you live in the USA and use a special promo code while ordering, you can now get this battery pack for as little as $5.09.
These are very useful backup batteries for the iPhone. They come with a built-in laser pointer, an LED flashlight, a dual voltage 110-240V AC wall charger, a USB/mini-USB retractable charge cable, a dual port USB car charger, and small support braces for most generations of the iPhone that can be used to hold the battery pack to the phone. The battery packs also work with all iPod models that use the Dock connector.
If you buy one, the price is $5.98, but for two or more the price drops to $5.09. Once again, the deal is only valid for US customers, and it ends at midnight on July 31st, 2011 or when supplies are exhausted. To get the deal, enter the code word fireworks into the coupon code box while checking out. For more details and to order your backup batteries, visit the product page for the RS001.