Are there items (such as additional content, offers or currency) for sale that are used in the gameplay of the product?

Yes. Players can purchase ingame currency to be spent in the game.

Can the product be used without making any in-app purchases?

Yes. The majority of items can be gained through traditional player progress. Critical things like performance upgrades, the fastest car or weapons and ammunition can always be gained without any in-app purchase.

Are in-app purchases refundable?

No. This is not possible.

What payment platform is used to facilitate in-app purchases?

Epic Games