Hey Michael,
When exactly did this start happening? Did you happen to install a new app around the same time that it started happening? As far as I know, Amazon only shows their ads on the lockscreen of Kindles with "Special Offers", and '''not''' on the home screen or in apps. I would try uninstalling your recently installed apps to see if that fixes the issue. If that doesn't help, I'd recommend trying to [https://www.amazon.com/gp/help/customer/display.html?nodeId=201830030|factory reset|new_window=true] your tablet. This will reset your Kindle to how it was when you first got it, which should wipe away those advertisements.