When it comes to birds, I prefer to stick with necks and backs. Long, hollow bones have a tendency to break into shards, and that just doesn't sit well with me. As for beef ribs, they are a bit too hard to count as RMBs but if they're meaty, you can use them for a boneless meal and just let her chew on the ribs for recreation. Just make sure they're big enough that she won't try to swallow them whole.
Ground beef and liver are both good. If you can find beef heart, that will cut your costs down a bit. Heart is typically going to be your most affordable muscle meat. And organs should make up about 10% of the diet, so be sure to grab some of that. Liver and kidney are going to be the easiest to find.