As an ebay / online marketplace sole proprietor, can I charge a handling fee expense on my taxes to compensate for packaging and time required to take to the shipper?

As a sole proprietor who exclusively sells online, how do I deduct on my taxes for the time required for listing products for sale, preparing products for shipping, hand delivering packages to the shipper, since I do not have a salary?  

Can I charge an internal handling fee for each item sold?