I use coupons if I have them -- usually for things like paper towels and dish soap. I meal plan around what's on sale at the time.
We buy large quantities of things like ground beef when they're on sale, and I portion and freeze them at home. We do the same with split chicken breasts - I butcher them into boneless/skinless breasts, dice up the excess meat for things like stir frys or fricasee's and freeze them. I make stock using the bones.

We buy pork loins and I cut them into "chops", portion and freeze them. It means a bigger shopping trip when we get all of those things, but then we don't have to buy meat for 5-6 weeks.