Does the iPhone 8 plus have a headphone jack?

Does the iPhone 8 plus have a headphone jack? - 1

No

No, not directly.
There's a small adapter cable with a Lightning plug to fit the phone and an audio chip in it to drive headphones via a 3.5mm socket - so you can use any normal headphones but they don't plug directly into the phone, they go via the adapter.

There are also some direct plug-in headphones with a Lightning plug and the electronics built in.
Apple are now supplying those or their own Bluetooth headphones, "Airpods", depending on the phone.

The iphone 8 comes with the 3.5mm adapter cable and wired lighting earbuds.

You can of course use any Bluetooth headphones you like & you can also buy Bluetooth-to-3.5mm adapters on ebay that allow any normal wired headphones to be used wirelessly with a bluetooth audio device like a phone or tablet etc.

No iPhone from the 7/7Plus on up has one.

No, it does not have it. If you want to connect your headphone with an iPhone 8 plus, you should probably use a headphone jack adapter to connect it.

They weren't brave enough to charge people extra for it

No

Maybe

No