Then, just go shopping in the e-Textbook store (or click HERE to browse thru all 77,646 that are there right now). The credit can be used for Rental or Purchase of any "e-Textbook" (which includes many books that are not, strictly speaking, only textbooks). All eligible Kindle books will have the box below displayed on the product page (right under the formats section):
You will want to carefully check on the book product pages, also, for which devices are supported -- some of the e-textbooks are only usable online, as they are essentially specially DRM'd PDF files. These books will say:
Print Replica: This Kindle book looks just like the printed book
Read it exclusively on our free Kindle apps for iPad, PC or Mac
Read it exclusively on our free Kindle apps for iPad, PC or Mac
I have seen a few others that were limited to Kindle devices only (not in a while, but I haven't look much lately, either). You can confirm on either the Order Summary (a link displays after purchase when using the web site) or your order confirmation email that the credit was applied. The credit is applicable to more than one purchase/rental, provided you find items under $10 (such as Jean-Paul Sartre: Basic Writings for $4.49), so you can actually end up getting one or more books free using the credit. If you are homeschooling, be sure to check out the Master Math series, by Debra Anne Ross, any of which would be free with the discount.
Some of the fine print:
Click the "Buy" button (or the "Rent" button if available), and the dollar amount of your code will be automatically applied to your or rental of an eligible Kindle e-textbook. If you have not used the full $10 value of the promotional code on your purchase or rental, we will automatically apply the remaining balance of your code on each of your additional eligible Kindle textbook purchases or rentals until you have used its full value or until the code expires, whichever occurs first.
Promotional offer is valid from December 30, 2011, through January 9, 2012, and subject to change. You must redeem the credit by 11:59 p.m. PST on January 9, 2012. Limit one credit per customer. Geographically limited to those with a US billing address.
Promotional offer is valid from December 30, 2011, through January 9, 2012, and subject to change. You must redeem the credit by 11:59 p.m. PST on January 9, 2012. Limit one credit per customer. Geographically limited to those with a US billing address.