Boo is an AI-powered writing assistant that helps you write faster and more effectively. It uses GPT-3 to generate copy, suggest ideas, and give you prompts, all within a simple text editor interface. It also comes with Markdown support to help you stay in the writing flow. It offers an introductory plan for $7.99/mo, which includes a one week free trial and a 30% discount for life on any future paid plans.