Iphone apps - How to make room without paying again for in-app purchases?

I'm thinking of clearing some space for new apps on my iPhone SE. I remember that when I shifted to my new phone, I had to re-acquire all my in-app purchases for a game app, but this didn't cost anything, since I'd already paid for them. I know iCloud wasn't involved because my iCloud account is in limbo.

Is there any way I can clear up the space on my iPhone, while also making it so that I don't have to pay for those in-app purchases a second time should I decide to return to that app?