Managing product info using document listing

Hi.
We are starting to study a solution for managing a list of products
using something near to document listing \ document detail templates.
I would like to understand if \ how it is possible to add certain key \
value pairs when the user adds a new document thanks to 'document
listing' template.
Right now, when the user clicks on 'add infomation' link, it enters some
date values and eventual metadata (only keys), than that get partially
displayed in 'document listing' template in the row of the new document
added.
Is it possible to mandate the insertion of, for example, a key called
'price' with its value when the user add new information on 'document
listing' template ? Could it be possible then to see the 'price' column
on the 'document listing' page and also its value in the row of the
documemt added ?
Thankyou in advance for every possible suggestion, bye.