about 101 US bucks. Not out of the question for a fancy restaurant, but it would be a lot for two people.
Some people in this thread are either teenagers or live in the middle of nowhere and have literally no idea what a fancy restaurant even is.
A real fancy restaurant. Like actual high-class fancy. Easily $200 per person.
A "nice" restaurant in a city, $50 a person after tax but before tip is normal.
In Japan, there's no tipping, and the taxes are rolled into the base price for presentation. The fact that there's no tipping doesn't make the meal cheaper; on the contrary, because restaurants have to pay their staff a living wage, the base meals are more expensive.
At gyu-kaku in the US, the cheapest buffet is $35 per person, the most expensive is $60.
At a random yakiniku shop in Kanagawa, an all you can eat buffet at 5000 yen per person isn't super cheap but it's also not super expensive. It's perfectly ordinary. If they lived in Tokyo it'd be FAR more. Luckily for them, they don't!
A yakiniku buffet isn't some stupid pop-up Chinese buffet. It's all you can eat high-quality meat that you get to cook yourself. You're paying for the experience in addition to the quality.
Anyway, given Amano's established appetite, I am quite glad that they went to an all-you-can-eat place. Avoids the unnecessary drama of "I said I'd pay, but she took advantage of it and ordered way too much!" No, this way, she eats her fill no matter what and it's fine. A bit pricey for a high school student, sure, but it at least doesn't scale with her appetite. Some good writing for once.