The customer can get around $30 off, and then stack the trade-in and the 25% discount to get this item for a minimal cost (maybe you can snag it for $30-$40 if everything is applied correctly). However, one thing to keep in mind is that Amazon might decide to remove the trade-in gift card and 25% discount at any point.
https://www.amazon.com/Kindle-Now-with-Built-in-Front-Light/dp/B07DPMXZZ7