TIFU by accidentally buying a $600 piece of meat

I've been getting really good at cooking meats and have done a few prime rib roasts for holidays. Thing is, I have been buying my steaks at Costco and for $120 to $150, we wind up with an absolutely amazing meal.

This time I fucked up by going to a local butcher instead and not being properly prepared. I new it would be a much better cut of meat and I was likely going to pay double what I'm accustomed to. The butcher asked if I wanted "prime". Of course, I asked for a PRIME rib roast. How many people? 10+, I always like a little extra. 7 full ribs, feeds 14 people. He pot it on the scale, 20lbs. He punched in the price, $30/lb. 20lb x $30/lb = $600. I nearly died. He already trimmed it and it was exactly what I asked for.

Hope I don't fuck it up.

For those that are curious, I roasted some garlic, coarse salt, fennel seed, and some crushed coriander seed in butter. The I rubbed the outside of the meat with it. I'll throw it in the oven at 425F to sear the outside. Then I'll cover it and cook it at 330F until it's 120F inside. Then I'm serving it with an herb gorganzola butter, mashed potatoes and some steam-in-the-bag veggi.

TL;DR I went to a local butcher and asked for a prime rib roast. I'm used to paying up to $150 for a large, high quality piece of meat. Nearly died when it rang up as $600. Hope it's good.