Originally Posted by ~Ray

you can do it like this...

index.com - main domain
sub.index.com - sub domain
index.com/folder - money page

create niche sub.domain with no outlinks/advertisements ... link it to the index page and to the money page.

get backlinks to the clean sub.domain and let the se bots find the index page and money page. That should help their domain/page authority which is a part of SEO.

Your sub.domains will have lots of inlinks and no outlinks. Links to other pages within the same domain are not counted as outlinks.