ChatGPT offers a permanent Free plan with basic access for all users....

https://jaspersmasterinsights.opalvector.com/posts/i-keep-searching-for-chatgpt-plus-trial-codes-what-should-i-do-instead

ChatGPT offers a permanent Free plan with basic access for all users. Occasionally, targeted promotions provide free trials for the Plus plan, which may require a payment card and auto-renew into a paid subscription