Ribs freeze great - so go ahead and save money by buying 10-20 pounds at once. Just don't keep them in the freezer too long (1 month, tops) because the high fat content causes them to spoil much faster than other meats. You could probably keep them longer using a vacuum sealer - but don't expect them to last longer than 2 months.
Having them in the freezer is wonderful for last minute appetizers that help make your guests feel really special!
To cook a rack of baby back ribs - thaw them out, salt and pepper them, and grill them over indirect, medium heat (350-375) for an hour and 20 minutes. Baste with your favorite sauce during the last 20 minutes of cooking. Nothing could be easier!