WALLA WALLA—I first learned of “Gross Out” in Seattle. My roommate Jeff, a produce guy to elite Seattle restaurant owners, had sous vide another delectable cut of meat. He was always in the kitchen, cooking up some chef-level deliciousness.

I wondered aloud how he was getting these amazing meat deals in a city so expensive, and he described to me a magical place where perishable and nonperishable foods alike, alongside plants and some truly random housewares, were all for sale at reasonable prices.

Still, the name he used sullied my first impression of the discount grocery paradise h...