There was a time not too long ago when you stopped at a service station for gas and maybe a soft drink or a candy bar. Although most now have morphed into convenience stores offering sandwiches, hot dogs, donuts and slurpies, few if any flaunt the restaurant-quality cuisine turned out at Mr. Kabob, located inside a Sunoco station at the corner of 12 Mile and Coolidge. Considering the fresh ingredients and generous portions, Mr. Kabob ranks high on any cost-benefit ratio. The twelve entrées, which include soup or salad and rice or fries, average around $7 for lunch and $10 for dinner, and many of the sandwich variations of those entrées cost less than $4. Indeed, prices are so moderate that one might consider a small side order of hummus ($3.95), smooth and creamy if a bit light on the garlic, or mujadara ($3.95), a more exotic lentil, wheat and onion combination that might be just a tad too oily. The pita, alas, like that served by most of Mr. Kabob’s competitors, is the plastic-wrapped, store-bought kind, unlike the wonderful fluffy variety baked in-house at La Shish or Assaggi.