Link from Amazon?

Hey,

I have seen many people selling or giving the method in which they will give you a backlink from Amazon.

I have see that mostly these people will drop your link in a listing on Amazon.

I have also seen many people on yt dropping links in Amazon reviews and even in their Amazon profile.

Is that really effective?

Ive seen sellers on PeoplePerHour.com selling guest posts on Amazon.co but I cant figure out how they are doing them...

These links can be bought here on BHW as well. There's been a recent thread about it.

Tried to find it now but was unable.

Are they powerful?