This popular blade is the single-edged razor. They are more easily handled than the double-edged blades, but of course they only have one usable edge. The other side is capped by a band of rolled steel for safety and stability. These blades are widely available and are generally very cheap. A common price for a box of 100 is $6-8.
Construction professionals use a flat, single-edged blade with a trapezoidal shape. These "utility" blades are used in special knives that expose a variable length of the razors edge. They are also widely available and of varying quality. They are priced from $6-$14 per 100.
Another common type of razor blade is the double-edged shaving blade. They are extremely thin and require substantial support for use. Blades of this type have been made since 1870. These blades are becoming less popular as consumers switch to electric and disposable shavers. They retail for about $3 for a pack of 5.
These funny-looking blades are hook-style utility blades. They are made for cutting and trimming carpet, roofing, and linoleum tile without damaging the surfaces below. The only sharp edge is inside the little J hook. They cost about a dollar each.
These industrial blades are for carpet knives. They are also used in heavy-duty scraping knives. They retail for fifty cents each.
A blade that is striking in appearance is the hair shaper blade. Longer and thinner than typical single-edged blades, these are used by hair-stylists. They fit into a straight-edge like folding knife with combing teeth that sit in front of the blade. Combed through the hair, it is very effective for changing the shape of a head of hair. These specialized blades are commonly platinum coated stainless steel. A pack of 5 retails for about $8 at beauty supply stores.
A razor blade built for more specialized use is the craft blade. These blades were developed to provide even more exposable blade-edge than the utility knife. These long blades are etched with snap lines to allow the user to break off the dulling point and reveal a sharp point behind it. These blades are less common and more expensive, retailing for around a dollar apiece.
A remarkable blade obviously with a specialized function is the rotary cutter blade. Rotary cutter blades fit into a rolling cutter knife and are used to cut fabric and plastic film. Do not mistake these for a pizza-cutter! They are small (45 mm diameter) and extremely sharp. These blades have marks one centimeter apart along the edge, presumably to show how far you have cut. These are the most expensive razor blades I know of, retailing for about seven dollars each.
This gallery of razor blades is not comprehensive. I have not included the multitude of X-acto blades types because they deserve a page unto themselves.
Razor blades are very useful tools, but they are also very sharp and capable of causing serious damage. Never cut towards yourself. If you have trouble removing a safety covering, do not place yourself in jeopardy by applying lots of force. Never slash your wrists. If you are thinking of killing yourself, please do not. We need you around. You are going to have to tough it out for awhile, but sometime in the future, things will turn around. Someday unbelievably soon, you will be at the front of a ship with the wind on your face screaming "I'm the king of the world!" at the top of your lungs. Well, maybe not exactly that, but something great, or at least something interesting. So please stay alive. For more information please visit The San Francisco Suicide Prevention Website.