How to let selected role submit multiple data for 1 node?
The Field Collection module will let you do a couple of helpful things here:


you can group a set of fields, ie store name, price so that this data is part of the same entity
you can embed links to add/edit/delete field collections right on the node.


Embedding the form in the node is trickier, but doable, and Field Collection will get you off to a good start. 

Once the Field Collection module is enabled, create a field of the type field collection on your content type. Set the widget to 'embedded'. Then go and add individual fields to your content type. 

There is basic documentation at https://www.drupal.org/node/1353926 and a video tutorial at https://www.youtube.com/watch?v=1V1ofpgUw-Y.