A: No, it is not possible to purchase a custom integration separately.
To request a custom integration, you need to choose a subscription plan other than the free plan. Once you've chosen an eligible plan, you can request a free integration.
Adding on, if you select a higher subscription plan, you gain access to free re-integrations. If you make frequent changes to your store, we recommend using plans with this feature.
For more information about pricing, please refer to the link below.