You really have to boil down the cost/calorie to determine the best bang for your buck.

In addition to other stores, I keep 6-8 cases of real MRE around, they have very high caloric value and are a must have if you can get a good deal on some. It's been a few years (I do need to rotate some cases) but I never paid more than 35-45 per case with the right connections. Kept in a cool dry dark basement, the shelf life on them is much longer than their inspection date.

I have a mix of MRE, Mountain House, and Augason Farms rations in addition to (store bought) canned goods. Conservatively though, I'm a rookie and only have about 30 days food for the 3.5 of us. Without a resupply, we'll run out of water before food.