Ebay offers Nisaku The Original Japanese Stainless Steel Weeding Knife | 2-Pack for $12.99 (reg. $21.99) free shipping.

Product Description:
The Nisaku Japanese Stainless Steel Weeding Knife boasts both straight and serrated edges that's useful for dividing plants, planting bulbs, flowers and herbs, digging out weeds, removing rocks, cutting through roots and so much more! A comfortable wooden handle allows for a good grip for all-day digging, and ensures you push into the soil with more control. Comes with a faux leather sheath.