added note pricing openai

app.py

@@ -112,7 +112,7 @@ with gr.Blocks(theme='Insuz/Mocha') as app:
 	gr.Markdown("# Private GPT")
 	gr.Markdown("This chatbot is powered by the openAI GPT series.\
 			 \nThe default model is `GPT-3.5`, but `GPT-4` can be selected in the advanced options.\
-			 \nAs it uses the openAI API, user data is not used to train openAI models.")
+			 \nAs it uses the openAI API, user data is not used to train openAI models. (side note: GPT-4 is currently 500 times more expensive than GPT-3.5")
 	chatbot = gr.Chatbot() # Associated variable: chatHistory
 	msg = gr.Textbox(label="Message")
 	with gr.Accordion(label="Advanced options", open=False):