We currently only offer pay-as-you-go options for custom plan users (above 30,000 search and/or 60,000 verification requests per month) when they have reached their quota specified by the custom plan.
Standard plans can only be bought via subscriptions. We do not currently offer pay-as-you-go, pay-per-use or unlimited requests pack for these.
If you need to use a paid plan for 1 month only you can cancel its auto-renewal.