How much is this fendi dress worth!?

Im trying to sell some designer clothing to a consignment shop, most of them look like they are from 1980-1990. They belonged to a friend of mine. Im not too familiar with designer names/worth. But i have a black fendi dress made of a sweater like material, its a turtle neck and it goes all the way down to your feet. The tag says Fendi Maglia, and it says made in italy. Does anyone have any clue how much it could be worth?|||if it is truly fendi and vintage: 300 resale price, thought it was probably originally 900 or up, but now full length dresses are going in and out of trends.|||I know that people would do anything for clothes that look like from back then. Especially if its fendi and made in italy it adds to it... in a designer store it would probably be from 300 and higher|||yea atleast $300