Some types of meat have great nutritional value but are for some reason overlooked or considered "second class".
Things like chicken/beef/pork hearts, ox tongue (was a rare treat in USSR!), chicken/beef liver are very cheap (like $4 AUD per kilo or even less) and can be eaten without literally anything going to waste (no bones etc.)
I was considering organ meats at one point, but unfortunately there's a bit of an ick factor to get over when you haven't been raised on the stuff. (Saying that, I used too eat liver as a child.)
