The 4 bucks isn't the point, neither is the delivery speed. Hell, it wasn't rattlesnake anti-venom, just the principal. As someone who has been on the net since 1990 I've run the gambit of good bad and ugly and even began to believe that Amazon was better than eBay.
But not really. Well maybe a smidgen, smidgen and a quarter, but eBay sucks so bad that isn't high praise.
So as a Prime member you can get something delivered for free on a certain date but there's no guarantee it'll arrive on that date or you can pay extra for speedier shipping but there's no guarantee it'll arrive any speedier.
Gotcha. Hell in a handbasket I tell ya.