Vacuum sealers are great. I have a "Food Saver" brand. FoodSaver bags = good. WalMart brand bags = bad. For long term it's worth the money, for something you know you're going to eat next week or this month it's not.
You can probably get 2-3 lbs in a bag easily and will probably double or triple the shelf life.
One more thing you can do is get oxygen absorber packets and put them inside before sealing for even more protection.
BTW metal can't rust without oxygen.
