If you ever sell your Mac, the buyer may want the box and you might get a slightly higher price if you have everything that came with your Mac, including the box.
People selling their boxes on eBay are just hoping someone is over excited and can't/doesn't read. They see a heck of a low price and jump on it, and then don't even realize the ad says box only.
People selling their boxes on eBay are just hoping someone is over excited and can't/doesn't read. They see a heck of a low price and jump on it, and then don't even realize the ad says box only.
Yes, if someone is selling an item and doesn't have the box, it can be very helpful to buy a replacement box off eBay. I've had sold mobiles with a box bought off eBay for considerably more than without a box, and it's certainly made it worthwhile buying a replacement box.
But you should bear that in mind - when you come to upgrade to a newer Mac, you may regret selling your box so quickly...