[ He simply nods. ] I had a book on my person when I gained entry. I used that for payment.

[ It's a simple explanation but the payment was just 'something of value.' Strange barely had any books of magic in his Venice exile to begin with, giving up one of them certainly counted as valuable in his mind (and apparently also in the carnival's mind).

Though, Captain Oblivious over here just doesn't get the inference that Chise thinks he's a fae. Instead, he just continues talking and yammering on. ] You'd think that, but I've found that there's an odd amount of them who prefer dancing of all things. After all, I've been to two fae balls in the space of a year.