Update: See here for a further extension of the free period:
Grok Code Free Trial Extended
Good news! The free access period for the grok-code-fast-1 model has now been extended and will run until noon on September 10, 2025 (PDT).
After the free trial concludes, standard pricing applies: $0.2 per million input tokens, and $1.5 per million output tokens.
Take advantage of this extra time to test Grok Code’s speed and quality. Thank you for your feedback!
Update: Clarification that the free period concludes at noon on 10th Sept (PDT)