Create the account first; billing opens next for Agent Travel API Hobby: $5 minimum usage/month with $5 credits included, or Pro: $20 minimum usage/month with $20 credits included, under the usage-token minimum contract; pricing_model: "usage_token_minimum". Use /signup?next=%2Fbilling from a first-value commercial_next_step for paid-intent signup. The billing page still routes you back to key activation if needed.