Would this app “CostPal” be permissible to use?

Bismillahi Ta’ala

Walaikum Assalam Warahmatullah,

CostPal is an independent, third-party digital service designed to help Costco shoppers save money by monitoring their purchases for post-sale price drops. Once users upload their receipts into the app, CostPal automatically tracks those items within Costco’s 30-day price adjustment period and notifies the user if any of them become cheaper. The user can then claim the difference directly from Costco according to its official refund policy.

The platform operates on two primary payment models: a credit-based model and a subscription-based model. In the credit-based model, users purchase small bundles of credits (for example, 10 credits for $0.99) which can be redeemed for individual services such as tracking a certain number of items or receipts. This arrangement represents a form of ijārah (fee-for-service), as each payment corresponds directly to a defined service, and is therefore permissible so long as the terms are transparent and the credits are not subject to arbitrary expiration. The second option is the subscription-based model, where users pay a fixed monthly fee (e.g., $2.99 per month) for unlimited use of the service and other premium features. This too is categorized as ijārah, since the user pays rent or a periodic fee for ongoing access to a legitimate, non-speculative service.

Although we have not conducted a detailed audit of CostPal’s internal terms and contractual structure, there appears to be no apparent issue that contravenes Sharīʿah principles. Both payment methods constitute lawful compensation for a defined service, devoid of interest (ribā), gambling (maysir), or excessive uncertainty (gharar), and therefore their usage seems Sharīʿah compliant in principle.

And Allah Ta’āla Knows Best
Mufti Faisal al-Mahmudi