This offer is only for those with a Kindle Fire with Special Offers (KFSO).
From the home page of your KFSO, swipe the top menu to the left until you see Offers, then press/click in order to see the current offers. At the bottom, you should see the offer for Get $5 off a $10 purchase. Click on the offer then click to change your 1-click Settings (yes, this is required for this offer).
The big catch on this deal is that you must have a valid Discover card on file, change your 1-click settings, then use the Discover card on a $10 or more physical purchase (no gift cards or digital items) by Oct 7, the items have to be “sold by and fulfilled by Amazon.com” and your card must remain valid until you do. Still, it’s up to half-off your purchase and you can change your settings after you fulfill the requirements.
If you don’t have a Discover Card on your account, you may not see the offer at all (you can try adding it and see if it shows up by the sign-up deadline of Sept 7); if it’s already your one-click card of choice, try changing to another card and you may get the offer to show (I doubt those who already default to Discover will see this bribe to switch). It also appears that you need to make sure that your card is up-to-date on it’s expiration date, etc, before you sign up. Finally, you have to do the change to Discover from the Kindle Fire registered to your account.
Although I used my PC to check that my card was up-to-date first and followed all the procedures on the offer page, I only received an error msg when I tried to sign up for this deal. It turns out, all that meant was that I needed to go back to the Offers page on the Kindle Fire and try again – the second time around I saw the “Apply Credit” choice, rather than the “Change 1-Click Settings” button!