Can you buy Apple Care from eBay after purchase iPhone?
Caveat Emptor

You might be buying a sealed, boxed product at a reasonable price…
…only to discover it's only valid in Outer Mongolia.

Different countries have different statutory requirements &amp; Applecare varies country to country.

I'd be more circumspect.

Read this before even considering it - https://www.apple.com/support/products/iphone.html
but make sure to swap to your own country via the flag icon in the very bottom right corner of the page before reading it.