GPT-4 Chatbot Development

Hello, I am a PHP programmer working on developing a platform that allows entities and websites to build and customize their own chatbot based on GPT-4. This would serve as a personal assistant or technical support for their websites or online stores. I have designed and programmed a chatbot using Python, but unfortunately, the cost is very high, averaging 3-7 cents per message. This pricing makes it challenging to offer an acceptable service rate to my platform's clients. I need you to redesign and reprogram the bot to provide excellent responses at a much lower cost. I will attach some platforms as examples that I want to emulate. Please translate this message accurately.