ChatGPT is the most popular AI chatbot. The free tier uses GPT-3.5, which is still capable for most tasks: writing, brainstorming, coding help, and research. You get 3.5 for free, with daily limits on GPT-4.

For everyday tasks like drafting emails, summarizing articles, or generating ideas, the free version is more than enough. The paid version ($20/month) adds GPT-4 and image generation.