When it comes to charging a fixed price, "flat rate" is a commonly used term. However, there are various synonyms that can be used in place of "flat rate" to add more variety and depth to your language. These include "fixed price," "set fee," "standard charge," "level rate," and "uniform cost." Whether you're offering a service or selling a product, using different terms to refer to a flat rate can make your communication more effective and engaging. Try using these synonyms in your next conversation or presentation to diversify your language and add more clarity to your message.