The only thing free on Ashley Madison is creating an account if you are a man.
As a man only when you subscribe can you send emails and start chats
Women can email and chat all they want without extra charges. They send Collect Messages. This means the member who is receiving the message can read it if he pays using credits. Very similar to how collect phone calls works.
Men can also send a Collect Message but when a woman receives one their first though is probably that he is cheap.