Saving money on meat - buying in bulk

It's moving slowly towards Winter here and soon the weather will call for hot soups and casseroles.  Hanno does a lot of our grocery shopping now but I was in the IGA supermarket the other day and nearly fell over when I saw a large leg of lamb priced at $40.  I thought it was a mistake, but looking at the other legs close by, I realised it wasn't - the smaller legs were $30 - $38.  I just