Amazon offers most of their Kindle devices in two versions: With or without “special offers”.
For $15 more you can remove ads from your device, but the better question is: Why would you want to?
The ads only show up on the lock screen or an occasional notification, and as soon as you open the device (or swipe it away) you don’t see it again.
So your standard usage of the device is never impeded by the “special offers” and once in a blue moon, you may actually see something that interests you!
When you buy your device, don’t spend extra to remove those ads…try them for a bit, you can always take them off later if they annoy you.