ChatGPT offers a permanent Free plan available to all users at any time....

https://holdenssplendiddigests.zenbloomer.com/posts/how-do-i-know-if-my-chatgpt-trial-will-auto-renew-and-charge-me

ChatGPT offers a permanent Free plan available to all users at any time. Occasionally, targeted users may get a free trial of the ChatGPT Plus plan. Some trials require a credit card and auto-renew into a paid subscription once the trial ends