It's the equivalent of the stuff next to the checkout of a retailer--it doesn't make sense to ship a $1-5 item on its own. I made an Amazon order yesterday and

It's the equivalent of the stuff next to the checkout of a retailer--it doesn't make sense to ship a $1-5 item on its own. I made an Amazon order yesterday and noticed an add-on item in my cart that I had saved from a previous session, I kept it on the order ("added on" you could say) and now I'll get the nail clippers I had been meaning to purchase as well as what I had originally bought. Happy Prime customer here.