The World's Most Expensive Root Beer Float

I think it's about time I do this again.

People will go to great lengths to feed themselves. In this installment, I'm going to build the world's most expensive Root Beer Float.

First ingredient: Root Beer.

Let me just Google "Most Expensive Root Beer" and...

Hold on.

Wait.

No.

That's not what I-

I didn't Google BEST Root Beer, I meant-!

GYAHH!

...

Apparently, I can't take the easy way on this. There's a "World's Most Expensive Marmalade" and not "World's Most Expensive Root Beer".

Let's check Ebay. That's my second best guess where I should look. Unfortunately, when it comes to expensive things regarding Root Beer, you'll find merchandise. Besides, I don't think you'd want to drink the contents of ancient, rare Root Beer. You'd probably die of botulism. What's Botulism? All you need to know is that you don't want it.

 Just buy a keg of Virgil's. It says "Gourmet" so that's good enough. This will run you about 21 bucks for the 5-liter keg. I don't care. It's the most expensive Root Beer I can think of. 

Usually, when you search for "The World's Most Expensive Ice Cream" you get this result.

You get this. I remember reading about this in the Guinness Book of World Records as a child.

"The most expensive dessert is The Frrrozen Haute Chocolate ice cream sundae costing $25,000 (£12,000), which was added to the menu of the Serendipity 3 restaurant, New York, USA on 7 November 2007.
The dessert uses a fine blend of 28 cocoas, including 14 of the world's most expensive. The sundae was made in partnership with luxury jeweller Euphoria New York.
The dessert is decorated with 5 g (0.17 oz) of edible 23-karat gold and is served in a goblet lined with edible gold. The base of the goblet is an 18-karat gold bracelet with 1 carat of white diamonds. The dessert is eaten with a gold spoon, itself decorated with white and chocolate-colored diamonds, which can also be taken home."

Okay, okay. I know what you're thinking: All you'd have to do is pour root beer on the world's most expensive ice cream. Hold on there, partner. That's too easy. And I say that that vessel is too lame for this.

This begs the question: What's the world's most expensive cup?

What's a cup that nobody's been able to find? What is a cup that everyone wants to find?

Yes. Oh yes. You think I wasn't going to go above and beyond? We're talking about a Root Beer Float served in the Holy Grail!

How much does the Holy Grail cost?

Supposedly, there's no way the cup of a poor carpenter has lasted that long, but if countless knights died looking for the thing, I might as well try to find where it is and what it costs.

While there are many cups that claim to be the Holy Grail, there's no way we can confirm that. Think about it. If it was the Holy Grail, and if you drank from it, you'd be immortal. As far as I'm aware, there's no immortal screwheads running around with an old cup, so it's fair to say that the Holy Grail is lost. For now.

Considering that it hasn't been found, for now, the Holy Grail can be considered priceless. So, what does that make our "Most Expensive Root Beer Float"?

Root Beer has water in it.

Ice Cream has water in it.

That leads me to one conclusion.

Price: $25021, but served in a priceless vessel.

Nutrition facts: Immortality.