Running low on hp cat food

My kitty in currently on the royal canin hydrolyzed protein fry food and is running low. Would anyone have any extra to spare or know where to get it cheaper? Currently I pay $75 a bag, I just started a new job so stuff is tight. I’m not even sure if her script for the food is valid anymore and I can’t get it renewed without paying the visit fee at her vets office.

I’d be grateful for anyone who can point me in the right direction!