запасаться(on/with; to stock up on meat – запастись мясными продуктами; to stock up with food for a journey – запастись продуктами для путешествия Taras)
покупать впрок(Stock up on foods that you normally eat on a day-to-day basis. Now I don't mean stocking up on things that can spoil, but you should definitely stock up on foods ... Alexander Demidov)