With all deference to Kuan, you're not going to get restaurant quality USDA "Prime" at Costco or the grocery store, you're going to find "select" or "choice" but that's not a bad thing for most civilian grilling/roasting. Dry aging at home doesn't have to take a week, you can probably improve a supermarket cut with as little as 3 days worth of moisture loss in the fridge.

For the few times a year that you do go out for a steak, make it the best you can find, otherwise, order the fish.