Checkout does not support an optional subscription checkbox on top of a one-time purchase

Aghanim Checkout does not currently support a combined flow where a player buys a regular item and can optionally add a subscription via a checkbox in the same checkout.

What is supported

• Subscription purchases can include plan selection within the subscription flow itself, such as the radio-button plan selector shown in Checkout.
• One-time item purchases and subscription purchases are handled as separate orders.
• You should create an order for either the one-time item or the subscription, rather than a single checkout flow that combines both.

Recommended approach

If your goal is to let the subscription grant specific content, configure that content inside the subscription rather than trying to attach the subscription as an optional add-on to another item purchase.

Items included in the subscription can be shown as subscription benefits in Checkout, and your backend can grant entitlements based on the subscription SKU and selected plan.

Backend handling

• Use the subscription webhook events to receive the subscription SKU and plan key.
• Apply your entitlement logic on your backend based on that SKU and plan.
• For recurring rewards on renewal, use LiveOps triggers on the subscription.renewed event.

Summary

You cannot currently offer a "buy this item + optionally subscribe" checkbox in the same Checkout flow. To deliver subscription-related rewards, model them inside the subscription product and handle grants through subscription webhooks and renewal automation.