In the majority of shops you find small objects with a very low price per item, just think to ironmongery or nail charm. Your customer could either be one who needs big amounts of such product or one who needs just a couple of small nails. Yet, in this case, shipping so few would require too much time if compared with the earnings you would get (not to say that earnings are entirely missing). And not to mention, then, shipping costs that would be much higher than the price of purchased products.