If you don't want to bother with learning how to sharpen tools, knives included, or if you only plan on buying pretty knives and don't want to chance buggering any of them up while learning how to sharpen, a sharpening aid probably makes sense as they can work very well in a given set of conditions. Otherwise learning how to sharpen freehand makes sense, and you can get started with a modest investment. In my opinion a good coarse stone is the foundation for a sharpening system, and so far I find that a set of three combination silicon carbide stones work well, as I can flatten them by grinding them against one another. They were about $6 at Sears. I sharpen chisels, planes, scissors, pruning shears, machetes, Xacto blades, lawnmower blades, axes, hatchets, etc., as well as knives.