AI21 Studio Free Trial ($10 credit, 7 days, no card required)
AI21 Labs
Free trial on sign-up: $10 of credit valid for 7 days, no credit card required
Verbatim from the official pricing page: "Start with a free trial, no credit card required, then pay based on usage." Free Trial tier: "$10 credits for 7 days. No credit card needed", the page button reads "Start Now for FREE", usage is paid after the trial, and there is also a custom tier for enterprises.
AI21 Foundation Models
The 7-day validity counts from the moment you claim and the credit lapses on expiry, so this is a short-term trial. The official pricing page does not list the specific models the trial can call, so go by the console. Reachability from mainland China was not tested.