I think that's 2,161,530,000,000 searches * $0.07/search (he mistook it for $0.07 per search)

On the other hand, your post mistakenly reads 0.07 cents per thousand, though you did the calculation correctly.

Math is hard, let's go shopping for data centers!

Given the phrase cost to serve 1000 searches are you sure I was mistaken?

He's saying that it is 0.07 dollars per 100 searches instead of 0.07 cents (which would be 0.0007 dollars).