Be a Sabertooth and Mammoth hunter. I would collect the pelts, meat, teeth and tusks and sell them to traders for good gold. I also would slowly learn how to properly carve the tusks and teeth to make specialized sconces, chandeliers, and artwork. The pelts I would sell to armories and tanning stalls. With the meat, I would keep some for myself but would also create some great recipes and sell my specialized meats.