The business between designer / fabricator to the interior design showroom.  

I cannot seem to find information anywhere relative to the conduct of business between designer / fabricator to the interior design showroom. I wish to know what the typical arrangement is for a designer / fabricator to submit her finished furniture products to reputable showrooms with the aim of securing representation in various locations. Does one provide the product as a floor sample to the designer free of charge, or does the interior designer pay for that floor sample from the designer / fabricator? Aside from quality, value and customer service, what does the interior designer look for from the furniture designer / fabricator. How can business be done that is mutually beneficial this way.

Any help with information in this area will be greatly appreciated! Gia Brassano.