Make tools unless you have too many already.
Start with fire handling tools and ahardy.
Then punches, drifts, a hot cut top tool.
Make a blacksmith's square,
A bevel guage, an adjustable taper guage.
Make some spring fullers and a scrolling fork or two.
Make a nail header, rivet and or bolt headers as well.
After you get all the simple stuff out of the way, make tongs. You can never have too many tongs.
From there move onto heat treated tools like cold chisels and learn that aspect of the craft.
Last but not least make hammers.
By now you will have the tools or the skill to make the tools to do anything.
like Thomas said, buying stock at big box stores is poor practice.
Make a rack along a wall to keep your stock dry and out of the way.