[Acroyali]

Where do you usually source your beef from? The grocery store or supermarket can be an expensive way to do it sometimes. If you haven’t already, could you talk to a local butcher about saving some quality scraps? Many will, or if you have freezer space, buying in bulk can help tremendously.
If she does well with beef, have you considered substituting beef heart? It’s usually cheaper, VERY high in taurine and a very nutritious additive. It’s considered a muscle meat, not an organ, and while some beef heart is fatty, many are pretty lean. Does she need 90%FF or is this just what you’re able to locate the easiest?
Another option is going right to the source and finding a local farmer that raises beef. You might be able to get scraps and meat for cheaper, especially if you’re able to buy in bulk and store in the freezer.
Another somewhat inexpensive thing to consider would be beef tripe, if you can handle the smell! I’m not sure if it can or should be cooked, but I know fed raw it’s great for digestion and teeth and has a good cal/phos ratio. Some people swear by it and say it’s the perfect food for dogs and (if fed alone) is a complete diet, but I’m not as 100% convinced that they need nothing else. I’m not sure if you’re into that idea or not, but if so it’s something you could definitely consider sourcing as it’s very inexpensive compared to “real” muscle meat!
You could also bulk the meals out with these things (heart or tripe), as well as kidney, liver, or tongue. I can feed tripe, livers, gizzards and all sorts of weird stuff but for some reason beef tongue really grosses me out so I don’t use it 😛
Assuming that she would do well on any “relation” to beef, I wonder if any hunters (or, again, butchers) would be willing to share venison, or if the butcher would have any leftover venison from last season…sometimes hunters have deer processed and then (for some reason) never come to pick the meat up. If she does well on beef, she MIGHT do well on venison, so this might be another option to keep in mind. It would probably be too expensive to purchase on it’s own, but if you can get a freebie…
Hope this is (somewhat) helpful!