system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can I get overnight shipping for $3.99 from Amazon (granted I used my dad's Prime account), but to overnight my mom an equally-sized box for her birthday through UPS was $95?
gpt
Part of it is the volume.

Amazon sends a lot of packages and they naturally have to pay different prices then somebody who just sends a one-off.

Amazon also has extremly streamlined their whole logistics process and integrated it with the ones who do the shipping so that actually taking a package from one of their warehouses is a whole lot of less effort than it is for most packages that are send.

Since Amazon sends so many packages it has a much better bargaining position that normal people to get the lowest prices possible.