naturally, knives get dull from extensive use. commercial sharpeners can sometimes be pretty expensive. here's how to get a very cheap, if not free, and effective way to sharpen a knife.
Step 1: What You Will Need
a knife of course
a light filament-- you can get these at Lowes for a dollar or two. if you have street lights, then when they change them, you can go over and ask for an old one. they are just going to throw them out, so they will probably say yes.