The most expensive thing I've had that was really notable (as I'm sure I've ordered something pricier and thought nothing of it) was half an A5 wagyu steak from Wegmans. I think it was originally around $250/lb but it was on a manager's special sale. I think it was around $80 for a ½lb, which is genuinely insane to me knowing that manager's special means it's the last chance to buy something before it goes bad.
Anyway, it was really good. A very odd experience though because afterwards I kinda stopped craving/ cooking/ ordering beef for a couple months. It was like I achieved some superlative thing and was just done with the concept of beef for a little bit. A strange reaction to such a positive experience, that said I do still eat beef occasionally.
We bought 1.5 kg of A5 wagyu for dinner on my brother's birthday, and then we ate the leftovers on bread for breakfast the next day. It was about $400. Don't think I'll ever get tired of eating beef. The thing about wagyu though is there's a lot of fat in it, so you'll be full quickly. I later ordered 100 grams at at restaurant and didn't need any more.
Yeah, the marbling is crazy, you can cook it and cook it and you'll never run out of fat in it. I only did a couple minutes on each side though so it was extremely rich. Even a ¼lb was probably a little too much when I had it. Non-hamburger beef is more of a treat to me at this point, I think I enjoy it a lot more when it's a rarer occasion.