Eat fatty cuts of meat, such as pork chops, pork belly, bacon, salt pork, pork butt roast, beef rib-eye. Save any grease that forms when you cook things like bacon. Slow cook fatty meats like oxtails, chuck roast, or soup bones and when it's done, put the juice from the crock pot in the fridge and then skim off and save all the fat that forms. Use that for cooking. You might ask the guys behind the meat counter if you could have some fat. They might just give it to you or they might charge you pretty cheap. Then take that home and render your own beef tallow or lard. And once in a while, roast a duck. It's a hell of a lot of work and not cheap, but you can get nearly a quart of duck fat from one duck. From now on, I'm having roast duck for Christmas instead of turkey.