Gemini offers a free tier that handles day-to-day writing and brainstorming...

https://www.animenewsnetwork.com/bbs/phpBB2/profile.php?mode=viewprofile&u=1206734

Gemini offers a free tier that handles day-to-day writing and brainstorming with ease. If you are a power user or professional needing deeper capabilities, the Google One AI Premium plan costs $19.99 per month