It just got a whole lot easier to decide whether or not saving $50 on Amazon's new ad- and bloatware-subsidized smartphones is worth the headache of having to see an advertisement on the lock screen every time you wake the device.
That's because you can get rid of the lock screen ads on the BLU R1 HD and Motorola Moto G4 without rooting either phone, simply by using a third-party lock screen app, as demonstrated in this video by Tim Schofield.
Since these Amazon phones will come with Google Play services installed, all you'll have to do is open up the Play Store and search for a lock screen app (use this link to go there now). There are a lot of third-party lock screens to choose from, but they basically all offer the same function—the biggest differences between them are aesthetic, so choose one that you like and go with it. You'll never have to see a lock screen ad on the phone again.
It's worth mentioning that you could also remove lock screen ads by disabling your lock screen altogether, but the risks far outweigh the benefits, so you really shouldn't do this. Having to look at an ad each time you turn on the display is a much better alternative than making your phone an easy target for attack or theft.