What is the '¤' character?

This is the currency sign

A currency sign is a graphic symbol used as a shorthand for a currency's name.

Also from Currency (typography):

The currency sign (¤) is a character used to denote a currency, when the symbol for a particular currency is unavailable.

The symbol is available on some keyboard layouts, for example French, Danish, Norwegian, Swedish and Finnish keyboards, because it is used in business applications.

Pillow character in the Travel Industry designates a Guarantee Sell vendor. Allowing visual confirmation of booking a transaction with a vendor that guarantees reservation.