* Prices may differ from that shown
A few years back I bought a cheap set of Kitchen Devil knives on offer at ASDA. They were razor-sharp at first, but after a couple of months it was starting to get to the point where using a desert spoon to cut meat would have been more effective than using the knives, since they blunted pretty quickly. I guess they were cheap for a reason...
I didn't want to splash out on any more knives (and I certainly didn't want to use my spoons), so we thought we would try to pick up a knife sharpener instead. Despite being rather wary of the Kitchen Devil brand at this point, we picked up this sharpener, again from ASDA for about £8. The price varies a fair bit depending on where you get it, and as usual, online prices can be a fair bit cheaper.
This item is plastic, and doesn't exactly look or feel expensive. However the handle is sturdy, slightly textured, and easy to grip. I guess I would have to recommend making sure your hands were dry before handling it, in case your grip slips, but I really hope that is common sense!
The actual sharpening stones, of which there are two, are ceramic, and are set a a slight angle from the line of the handle, this ensures that both sides of the inserted blade gets evenly treated. These ceramic parts are guarded by a clear plastic shield, with a slot in the middle to put the knife in. This is pretty handy, as it keeps your knife in the correct position, and makes sure it doesn't slip left or right. I have never even come close to slicing of a finger whilst sharpening, so it must work fine (finger slicing whilst cutting is another issue altogether that I won't go into here). This guard can be removed to access the sharpening blades if required, but so far I have never had to do this, and don't intend to if I can help it.
The device is suitable for any straight edged knife. Don't try to use any serrated blades on it, as it will just ruin them. I have found that long knife blades are easier to sharpen than small paring knives, for example. The clear plastic guard I mentioned is fairly bulky, and if the knife handle is also thick, you may struggle to get the area of blade nearest the handle to run along the ceramic sharpeners.
The instructions recommend swiping the knife a half dozen times or so in each direction (back and fore) in order to be effective, but I always give it a good few extra swipes each way (for luck). I do find that the sharpening doesn't last that long, but I reckon that is more to do with the rather cheap nature of my knives, and possibly because we cut all out meat on a glass board. Maybe a softer material to rub against the blades would prolong them? Maybe I shouldn't buy such rubbish knives?
My, um, thriftiness, towards knives aside, so far this little device has kept four knives well in service about two years longer than they would have otherwise lasted, so for eight quid, I would say that's pretty good value. It is guaranteed for ten years, so hopefully I will get many more years use out of it, although I may have to buy some new knives by then, or I will be sharpening little stumps.