I found topside steak to be good.... it's usually really cheap, and you get big pieces with hardly any fat. And the fat is usually around the edges anyway so it's easy to remove. The steaks are thin, but at least they're big and cheap.
If you can find it Bison meat is very lean, many different cuts. I know the ground Bison has less fat per serving than shrimp. Some fat is good just keep the sat. fat low. Go to a health food store and look at all the nutrition labels on the different types of meats. I am sure you will find several that will work for you. The small bacon wrapped filets are good just remove the bacon and its lean and yummy.