The availability of a free login option for ChatGPT impacts the user experience by allowing users to access the basic chat-based features without a subscription fee. However, users on the free plan may experience limitations such as potential wait times during peak usage and slower response times. The paid subscription, ChatGPT Plus, offers an enhanced experience with faster and more consistent access. Users should check OpenAI's current pricing and subscription models for the latest information on free and paid access options.