Any meat is free as long as ALL visible fat is taken off, so that includes steak, bacon, chops, whatever - you have to take ALL fat off - but you dont have to go and buy any special kind of meat. However, depending on what sort of meat you're looking at you might have something that fat is hard to remove from eg when the meat is 'marbled' etc so account for this when you buy it - you'd have to syn it so is it worth buying?
Also stuff like mince and sausages you can't remove fat from, so buy the leanest you can. Mince has to be Extra Lean ie <5% fat to be free. Sausages you need to check out the syns online for which ones are lowest (no supermarket ones are free) there are loads of threads here with that info in.