In a large pan, cook the sausage in a fry pan until it crumbles and cooks through. Drain grease because it's nasty. Remove from pan. Add butter to pan and saute the celery and onions. Put vegetable mix in a large bowl. Add the stuffing mix, turkey broth/stock, and cooked sausage and mix well. Coat a large pyrex casserole dish with cooking spray and add stuffing pressing evenly. Bake at 350 for 30-40 minutes.