The reality is is that shipping an amazon item costs between $3-7. For expensive items, they can cover that cost out of the wholesale/retail markup, so you don't really have to pay it. For cheaper items, or items without that much of a markup, it starts showing up in the price. Now, sometimes a manufacturer will want to buy some market share, so they'll sell an item to Amazon cheaper to reduce that impact, and then it's available. However, it will usually go back up to the normal price, with them hoping that you won't notice.