Its okay, if you want to actually be successful in your business dont require so many purchases to actually enjoy the story. Perhaps have stories that you can only buy, and stories that are free. But having to pay to even view photos isnt fun, and makes the developers look greedy. Even in Hooked, the app thats very similar to yours, you dont have to pay to see photos. If you want business, find different things to pay for rather than taking away from the experience. Good luck with your company! Ill be uninstalling since there are much better and much less costly apps like yours.
MarissaGhost about Yarn - Chat & Text Stories, v1.5.0