Grok’s paid plans start at $20/month for up to 10 prompts every 2 hours, with...

https://wiki-planet.win/index.php/What_Does_Grok_Heavy_Mode_Actually_Do%3F_Exploring_Multi-Agent_Parallel_Execution

Grok’s paid plans start at $20/month for up to 10 prompts every 2 hours, with an option at $50/month for higher usage. There’s no free trial, so you’ll pay from day one