Your account is currently on the Hobby plan with a trial credit balance of $3.47 remaining from the one-time $5 trial grant. Once the trial period ends (30 days or when credits run out), the Hobby plan costs $5/month, not $1, and that $5 subscription fee includes $5 of resource usage credit. You can review full pricing details at railway.com/pricing.

And why does it say here after the trial period, the next one will be $1? "Start with a 30-day free trial with $5 credits, then $1 per month"