You can't beat some of the deals at the Commissary - so much lower than off-base. Maybe not exactly the selection of other major grocery store chains, but it's definitely worth it, and they aren't missing much. Lots of fresh produce, seasonal stuff - they've got it covered! Plus, they're definitely keeping up with technology, as they even have self-scan.
And where else can you get a pink Nellis tshirt for $7 Oh yeah.