The New Texas Oilfield is a region that is made up of two towns, Verdammter Platz and Diep Gat. It is protected by Desert Patrol. It is one of the only places to get crude oil, and usually your first chance to buy cars.
Please note that these have a VERY UNRELIABLE SOURCE OF FUEL. BEFORE YOU BUY A CAR, MAKE SURE THE MARKET HAS FUEL, OR ELSE YOU'RE SERIOUSLY SCREWED.