score:3
If the item can be bought on Amazon, and will fit into an Amazon locker, there are many such locations near Newark airport that should be easily reached within in your time frame.
From what I understand, once an item is delivered you have up to 3 days to pick it up. But the challenge is to predict the delivery time so that those 3 days overlap with your layover at Newark, and I'm not sure what happens if you don't pick the package up.