I was looking for some LED bulbs for my trailer. I found a bulb that I like was getting ready to order it.

Based on how my corporate network works, my computer looks to many web sites like I am located
in NYC, which I am not.

Leaving it as the default zip of 10001 (NYC), I can get Free Prime Same Day *delivery*,
total cost $12.98.

If I use the shipping drop down to change it to my actual zip, the item is not eligible for Prime.
It's $9.99 + $2.99 shipping, total cost $12.98.

But wait...there's a link that says "Avaiable with free Prime Shipping from other sellers on
Amazon". If I use that link, it is eligible for Prime and I can get Free 2 Day shipping,
total cost $12.98.

So, obviously the Prime shipping isn't really free and your location matters and the
seller matters. It's obvious that Amazon wants you to join Prime because they point
you to Prime-eligible sellers for the same item, even though the total cost is going
to be the same. The only difference might be the 2-day shipping via Prime vs.
standard shipping when you actually "pay" for shipping separately.