He said Big Mac Meal. Where I live, outside of California, it’s $10.49 for a medium, and $10.99 for a large according to the McDonalds app.

A big mac meal is about that price, or lower, at any McDonalds I have been to in southern California. I spot-checked a random location by me: $6.29 for the sandwich, $9.69 (before tax) for a medium meal, $11.19 for a large. That's about double what the menu price was in suburban Chicago ~20 years ago.

Extrapolating from the map, I don't know where even a large big mac meal would cost $18 in CA

That's not the price of a meal. I'm not sure if you get all the way up to $18 after making it a meal and adding tax/tip/etc but it's insane that McDonald's charges anywhere near that much for their bottom tier food.

I was cleaning my car out yesterday and found a McDs receipt from my son. He spent $17.47 on a quarter pounder meal near Seattle last summer. He did add bacon for 1.99 plus tax, but it is possible to get up around $18 for a single meal. I'm sure the prices are higher today.

I don't think McDonald's accepts tips.