Received an email saying free battery and shipping at trade tested for greenworks kits. Ended up getting the 40v mower. So it was 2x 4amp batteries and one mower (steel deck, 55L catcher) shipped (free) for $499.
That's father's day, my dads birthday and Christmas all ticked off in one purchase. He's old school and will hate it so I obviously haven't told him. Once he tries it I'll never hear the end of it.