From Rigor's post farther down...
Each promotional offer ("offer") claim code can be used only once.
• Each promotional offer (Save an additional 10% on Music gift ideas with your Amazon.com Visa Card when you spend $50 or more (Maximum savings of $20 per customer); Save an additional $5 on the hottest DVDs of the year with your Amazon.com Visa Card when you spend $50 or more; and Save an additional $20 on the coolest electronics, computers and cell phones with your Amazon.com Visa Card when you spend $200 or more) is an independent offer, and products may not be combined to satisfy purchase requirements.
• Limit one offer of each type per household.
• Offer must be redeemed at http://www.Amazon.com toward the purchase of products sold by Amazon.com. If Amazon.com is not the seller, it will be noted on the product detail page.
• Offer may not be used in conjunction with the purchase of products sold by or under the brands of third parties, including, but not limited to, Target.com, or any Apparel & Accessories merchants, or sold through third-party areas such as Amazon Marketplace. Offer cannot be redeemed at Amazon.ca, Amazon.co.uk, Amazon.de, Amazon.fr, Amazon.co.jp, or any other Web site operated by Amazon.com, its affiliates, or third-party merchants (including Web sites linked to from the http://www.Amazon.com site).
• Offer cannot be used to pay for special-order titles, e-books or downloadable e-content, gift certificates, gift-wrap, taxes, or shipping and handling charges.
• Taxes, gift-wrap, and shipping and handling charges do not apply toward the minimum purchase amount.
• If you are ordering items to be shipped to more than one address, a separate order will be created for each address. The promotional offer will be applied to only one of the resulting orders provided that order meets the requirements of the promotion.
• Some offers may not be combined with other offers, including other promotional certificates.
• Each offer is valid for a limited time only and expires on the date specified in the offer.
• Offer's cash value is 1/10th of one cent.
• Offer is not for resale and is not redeemable for cash.
• Offer cannot be applied to orders already placed with Amazon.com.
• If you return items purchased using a promotional code, you will not receive a refund for the amount of the offer.
• When you redeem an offer, Amazon.com can tell that you are part of a select group of customers (for example, Amazon.com may be able to tell that you are a customer of the merchant that provided you with the offer). For more information about data that Amazon.com collects from our customers, read our privacy policy.