Knife making is a intricate and sometimes hard process, good craftsmanship is essential. Many knifes today are not good quality. Especially sheath knifes, and too get good quality the big businesses charge too much (btw**dont buy a sheath knife if it isn't full tang). Many people do not care about the quality though. If you do keep reading, in this instructable I will show you the best materials for knife making without a forge (I mean seriously how many people have a forge). Forging is rather expensive due to coal prices and equipment costs.
So if you are the kind of person who is interested in things of this nature read on, if your not well CYA.

Step 1: Lawnmower Blades

Lawnmower blades are very useful. They are made out of industrial steel and already thin with little curves at the edge, that can be flattened with minimal effort. The only draw back is the width of the blade. It will need to be grinded down with a grinding wheel or angle grinder unless you want a flipping big knife, or machete.

Step 2: Scrap Metal

Scrap metal can some times be the only thing you can get, but be careful not to get copper or aluminum. Aluminums is lightweight, but it bends far to easily which is not good for a sturdy knife, and it does not sharpen well, the same goes for copper exept for the weight it is rather heavy.

Step 3: In a Smiths Case

If you do want to forge, car shocks are excellent. They are pure industrial steel, because they have to absorb the shock from jolts and bumps the car experiences during driving. Sorry couldn't find a good pic.