Cingular wireless coupons are codes - also mentioned as redemption codes -, consisting of 8 or 10-digit alphanumeric codes which are used in specific marketing promotions.

When you purchase a ringtone or graphic on the Cingular web site, you can redeem your coupon code at checkout and download the selected ringtone or graphic free of charge.
Using a coupon, you'll need a DirectBillCingular ID and password, enabling Cingular to identify you when sending the download you selected.

Usually the coupon codes can only be used once, unless notified otherwise.
Cingular also indicates: "Coupon Codes cannot be used for Direct-Download Wireless Internet and Text Messaging (SMS) purchases at this time. They can only be redeemed on this web site.
All customers with compatible phones and features are eligible.*
*Content delivery charges such as airtime or data usage still apply. "

At checkout on the Cingular web site, the screen may show "Charge to Phone Bill"; this is a standard entry under payment type.
But don't worry, nothing will be charged to your Cingular bill when you use a valid coupon code. The purchase-amount will appear as $0.00.
You can also verify this later, by logging in to DirectBill (www.cingular.com.db) and check your charges. Your ringtone or graphic purchase will be shown with a charge of $0.00. The DirectBill charges are updated within approx. five minutes of the purchase.

Of course, if you did not use a coupon code, the amount of your buy would be shown on the checkout page.

cingular cell phone service plans