Yes, you can create a chatbot for free. You can also upgrade to a paid plan to get more features.
From the blog
Custom model training and fine-tuning for GPT-3.5 Turbo
Today OpenAI announced that businesses and developers can now fine-tune GPT-3.5 Turbo using their own data. Find out how you can create a custom tuned model trained on your own data.
Unleashing the Power of AI: Adding a ChatGPT Chatbot to Your Website
An AI chatbot can serve as a dynamic tool to improve your site's user experience by providing instant, accurate responses to your visitors' queries. However, not all chatbots are created equal.