Can I pay once instead of subscribing?

There is no one-time image package, but you do not need to subscribe for longer than you render. A commercial product needs a paid plan while renders are delivered: subscribe to Pro for the month you render your set (25,000 credits are included, one per image), download the files or mint long-lived signed URLs, and cancel at the end of the period if you have nothing more to render. Everything delivered on the plan keeps its commercial license.

Buying credits on Free costs the same per image but carries only the evaluation license, so it does not replace that month of Pro for commercial work. When your product later adds a vehicle, a color or a view, that render needs an active paid plan at the time; most customers keep the plan for that, because it also keeps the hosted URLs renewing and brings re-renders as the pipeline improves. Use get_pricing for current prices and create_checkout_link to start a plan.