I'll also (if this was what the others were referencing) heartily recommend a Kabar Dozier Folding Hunter as a GREAT low cost folding knife. I'm finding it for sale online for just under $20 (add shipping).

This is the folding knife (3" plain blade, black handle) I bought for my kids - under the thought that if they lost it then I'd only be out about $20. My son almost lost his while at Scout camp, but I happen to notice a Scout using a knife that looked just like the one he'd lost. I voiced admiration, asked if I could see it, and it had my son's initials scratched on the handle. Heh heh heh. He finally admitted he'd found it on a trail.

It has been tough enough for what they've put it through, light weight, and to me sized just right for EDC.

I notice that they now have a "Mini Dozier Folidng Hunter" with a 2-1/4" blade. That might suit your needs too - I know I prefer to carry the mini Rittergrip, though I have several regular Rittergrips.

By the way, if you want to learn to sharpen knives, I will STRONGLY recommend purchase and use of the Spyderco Tri-Angle Sharpmaker. It is awesome and makes sharpening knives, scissors, ... super easy. Search Youtube.com using "Spyderco Sharpmaker" to see a bunch of videos showing its use.

By the way, the Sharpmaker's standard angle is 20 degrees, which works for most knives, but it also has a 15 degree angle for back-bevels, which I use to sharpen the Rittergrips (which came with a 15 degree bevel).