A "charge" és a "fee" között van valami szabály, mikor melyiket használjuk? Vagy az egyik a hétköznapi használatra van, a másik meg hivatalos levelekhez?

"As you can see, both words refer to the money paid for a service. Professionals such as lawyers and doctors generally use the word "fee" to describe the payment they ask for their services. "Charge" sounds less formal and is often applied to small amounts of money paid for a service."