Midway is having a sale on their Meyerco Tactical Folding Knife 3-3/4" 8CR13 Stainless Steel Tanto Blade, and at $19.99 you'd be hard pressed to find a somewhat disposable rough-use knife. 8CR13 is similar to AUS8 steel, and while I personally have found such blade material to be too brittle for longterm use, for a little over 20 bucks including shipping this would be a good stocking stuffer, or just another decent blade for the toolbox.
You can get the same knife in drop-point and I've included the Tanto simply because its my favorite. Just goes in then out easier. And of course the blade is less than 4" in length because we wouldn't want to offend the states that make it a crime to carry real steel.
The children. Think of the children.