Amazon Ebooks - Spend $10, Get $3 YMMV

https://www.amazon.com/kr/d6e5aa2...49f2a9e6e6

I found this offer while looking at digital magazines. At the bottom on the page it stated "by invitation only", so I'm not sure how many folks this will work for.

Get $3 back in eBook credit when you spend $10 on eBooks.
Sept 3 - Sept 10

How it works
1.Click Activate any time during the offer period. Eligible purchases made before activation still count!
2.Spend $10 on any eBooks by Sept 10.
3.Get $3 back in eBook credit to spend on any eBooks.

Terms & Conditions
This offer is by invitation only.
This is a limited time offer.
Offer applies to all Kindle eBooks made available through Amazon.com and smile.amazon.com, including pre-orders that are fulfilled within the offer period.
Offer does not apply to eBook pre-orders that are fulfilled outside the offer period, physical goods, digital magazines, audiobooks (including Audible companions for your Kindle eBook purchase), print books, or digital subscriptions such as Kindle Unlimited.
To receive a promotional credit, you must (1) activate the offer any time during the offer period and (2) purchase the specified amount on any Kindle eBooks by 11:59 PM PDT on Sept 10. You will then receive a promotional credit, and this credit will be automatically applied to your next Kindle eBook purchase. Any Kindle eBook sold on Amazon.com is eligible for this credit.
Offer limited to one per customer and account.
Offer is non-transferable and may not be resold.
Digital content and services may only be available to customers located in the U.S. and are subject to the terms and conditions of Amazon Digital Services LLC.
Within 4 days of activating the offer and spending the specified amount on Kindle eBooks, you will receive an e-mail from Amazon that indicates that the promotional credit has been applied to your customer account. The e-mail will also provide instructions on how to redeem the promotional credit. You can view your available eBook credit balance on any Kindle eBook detail page.
Your eBook credit expires 21 days after it is applied to your account.
Taxes and add-on purchases to the qualifying purchase (like an Audible companion) do not apply when determining minimum purchase amount.
Amazon reserves the right to modify or cancel the offer at any time.
If any of the products or content related to this offer are returned, your refund will equal the amount you paid for the product or content, subject to applicable refund policies.