How do I insert the node ID into a link field?
Going from node/6 page to profile/6 page (which displays products and reviews) there is a simple module that can help with this https://www.drupal.org/project/field_token_value
It will allow you to add a field PROFILE PAGE hidden from the editor and can be configured to have the value of
&lt;a href='/profile/[node:nid]'&gt;profile page&lt;/a&gt; 

after that go to the content type display admin/structure/types/manage/CONTENTTYPE/display to configure where should be displayed
The field will not be available on the edit form and after saving it will hold a link to profile/[nid]
Above module works in both drupal 7 and 8
More involved alternatives
you could use https://www.drupal.org/project/linked_field and https://www.drupal.org/project/field_permissions (drupal 7 &amp; 8)
For drupal 7 projects https://www.drupal.org/project/token_field does the same thing