A nice, potentially free hoe that works as well as a store bought one.
Step 1: Acquire Materials
You are going to need a piece of a leaf spring around 4 inches long. To cut it, I used an angle grinder with an abrasive wheel, but a torch or plasma cutter would be better. You will need a handle, and I used a 1"/1"/2' square steel tube (again, cut with angle grinder).
Step 2: Tools
If you use the same design as I did, you will need a welder, cutting tool, and a bench grinder (optional, especially if you have an angle grinder).
Step 3: Assemble
Weld the hoe with the back of the blade piece level with the back of the tube. If you wanted to, you could cut out a larger section of spring and make other parts on the back (root cutters, etc.). Sharpening makes it function a little better, but it doesn't really need it. Leaf spring is fairly strong, but the components don't really matter.