Developer products have MarketplaceService.ProcessReceipt but game passes do not get reported on this callback.
I check for what game passes a player has when they join, and because these values cache I then store that info for use during the players session. I think I could simply check again, but how will I know when to check or when the player has completed the prompt? Is there some event I don’t know about to reliably know when the player has completed a game pass purchase prompt and the results of it?
The wiki really needs help in this department. the MarketplaceService wiki page page barely has mention of PromptGamePassPurchase, just a small clip of code at the bottom. An mention of it with links should be at the top of the page with the rest of the “notable” functions and events.