When it comes to fees and costs, it can be helpful to find alternative ways to express the concept of "additional charge." Some synonyms for this term include "extra fee," "supplementary cost," "added expense," "incremental charge," and "surcharge." Each of these options conveys the idea that an extra amount of money is being requested beyond the initial cost. Using synonyms for "additional charge" can help to avoid repetition and also make it easier for readers or customers to understand what they are being asked to pay. It's important to choose language that is both clear and concise when discussing fees and costs in any context.