An aluminum carport, the kind you see advertised for $600 or $ 700 dollars, works perfectly for hay. For a little more money, you can close in the sides and ends. If you need to lower cost, close the sides and use tarps to close off the ends for now.
As for a barn, I would either build a large run in shed for now or put up supports and a roof on the footprint of the size barn you'd eventually like to have - just the poles and roof. Finish the side that faces the prevailing wind if you have the money. That's adequate shelter for now, and a place out of the rain. You can make stalls as needed with livestock panels (metal corral panels) and finish the rest of the barn as you have money and time.
As for a barn, I would either build a large run in shed for now or put up supports and a roof on the footprint of the size barn you'd eventually like to have - just the poles and roof. Finish the side that faces the prevailing wind if you have the money. That's adequate shelter for now, and a place out of the rain. You can make stalls as needed with livestock panels (metal corral panels) and finish the rest of the barn as you have money and time.