HM... check out the thread in Dog Health, What Did Your Dogs Eat Today?. It can give you an idea if you look through all of Sarah's posts in a week (she posts the most in that thread ). My schedule for Gonzo is usually something like (for a 40 lb active dog)...

Monday: 2 Chicken wings for breakfast, .3 lb beef brisket meat for dinner
Tuesday: Lamb shank for breakfast, beef rib for dinner
Wednsday: Chicken leg quarter for breakfast, veggie mush for dinner
Thursday: 2 Chicken wings for breakfast, chicken leg quarter for dinner
ETC!

They get supplements almost every day, but that is up to you. I occasionally give them some yogurt, milk, cottage cheese, etc. I almost never give starchy biscuits & such, except one cookie before they go to bed. I use tiny bits of cheese, cooked chicken, liver, and pieces of carrot for training treats. The book explains basically everything you would want to know... and more! hehe. Grocery store meat is fine, as long as it isn't over-priced! A common rule of thumb is, for your main meats, don't ever pay more than $1/lb. I occasionally pay a bit more for special treats, like rabbit. His Farmore raw costs $2/lb, but that includes veggies and supps in it, and I feed it much less often. If your grocery store has no good deals, check out a different grocery store (Costco can be a God-send sometimes) or local butchers.

I recommend, next time you got to the store, ask the butcher for a beef femur bone cut in 1/4ths or a pack of soup bones (really, really cheap). Give it to Roxy to chew on, and watch her. Just rec bones regularly will help a lot, and prove to your Mom that it will improve her teeth.