No, that is not true. The item is not worth "what you need to get for" it. It is worth what a seller will pay. Otherwise keep it and save yourself the fees for a failed sales attempt. The best policy is to advertise it properly and list it long enough for the marketplace to decide what it is worth. You can always take it to a dealer and receive what it is really worth to someone else who has to make a living selling what you don't want anymore.
This is true, but if you need to get more than that, your price should reflect that. The listing fees can be much less to lose than an item that you lose a lot more on.