How do I create a free Consumable In-App Purchase?

I have already created consumable in-app purchases in App Store Connect which are available in my app.

Then I created a "Discount Code" UIButton which presented custom UI for the user to input a code for another in-app -purchase at a lower price but that build was rejected because you cannot have custom code for this sort of thing.

Ref: Apple Documentation: presentCodeRedemptionSheet()

Finally I got it through review when I changed the UI but then I realized that I can't offer a free consumable in-app purchase. The minimum price is US$0.29. I would prefer a free consumable in-app purchase to give to freelancers I am owkrin with for them to test the app with.

I know that there are ways to do it when using subscriptions but my app only using consumable in-app purchases which align better with my business model and the value offering of my app.

There must be some way of creating a single-use free consumable discount code which will also get through App Store Review.

Anyone managed something like this?

Thanks.

Testing is best done with TestFlight:

TestFlight makes it easy to invite users to test your apps and App Clips and collect valuable feedback before releasing your apps on the App Store. You can invite up to 10,000 testers using just their email address or by sharing a public link.

Alternatively, you can use Promo Codes:

Promo codes for in-app purchases

When a customer redeems an in-app purchase promo code for a free app that’s not installed on their device, the app automatically downloads. ... You can provide up to 100 promo codes for each in-app purchase product, with a limit of 1,000 total codes for all in-app purchases for an app every six months (resetting on January 1 and July 1). These codes are for non-commercial use and expire 28 days after they were generated.

How do I create a free Consumable In-App Purchase?
 
 
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