Brings back memories of the Chevy cars I owned back in the 1960s, like my '57 coupe. A key for your Chevy would often work on several of your friend's cars. If you weren't carrying the key, cross a couple wires under the dash and start by briefly tapping a third wire. Or under the hood via the starter solenoid. Once when I was 17 parked at a drive-in restaurant, a pretty gal came up to me and asked if I could hot-wire her car. Her date had argued and taken her car keys. So I lay on the floor under the dash while she and three other pretty gals in the car watched me. Hard to concentrate with a gal in a mini-dress sitting in front! Got a safety pin from her, pierced two wires, tapped the third (perhaps purple), and she was happy as can be. So happy she thanked me later (another story).
Side note: you can rig an electronic gadget to start your '57 Chevy that operates via an Apple watch. Or other remote, been done for years with a few bucks in parts.
I have had an interest in key making for quite a while. I have one of the inexpensive key cutters that they used to include in locksmith correspondence courses. I bought it at an antique store; it didn't look like it had been used more than a couple of times.
There are a number of suppliers on the Internet that sell tens of thousands of different varieties of key blanks. The plain ones are usually around $.25. The blanks that look like keys but have programmable chips in them are usually only a couple of dollars.
Sometimes the suppliers charge enough for shipping that it is cheaper to get blanks through eBay or Amazon. The dealers will charge you up to a hundred bucks for the programmable ones; most of them can be programmed by placing them in your car's ignition and following a special procedure and don't actually need a special programmer.
The ones keys that are a total rip off are the ones that don't even look like keys... some of them can only be obtained through a car dealer and then you are stuck.