How much is Grok AI?

Could you please clarify the pricing of Grok AI? I'm interested in understanding the cost associated with this platform, whether it's a one-time fee, a subscription model, or something else entirely. It would be helpful to know if there are any hidden charges or additional costs that I should be aware of before making a decision. Additionally, is there a free trial or demo available to try out the features before committing to a purchase? Thank you for your assistance.