I want look into to making some 12-gauge stingers for myself in order to save money. Is this relatively easy to do if I buy cable and the end pieces at a hardware store? Anyone have any words of wisdom?

One: don't reverse the polarity.
Two: check up on your insurance coverage.

The theater where I volunteer makes all sorts of power cables this way. But often enough, incareful work causes hazards.

One thing I like about newer stingers coming out is they have LEDs in the endpieces that tell whether they're powered or not. This is very useful in troubleshooting: is the problem with the power source or the lamp? No more having to pull out a tester, or plug other appliances in, or walk the several football fields away where the generator is hiding...

Is it really that much cheaper to make them???

Benjamin,

I made some dimmer boxes to use with my lighting and much to my surprise it was cheaper to buy an entire extension cord with molded ends than to buy a single edison plug with screwable ones. This was at Home Depot. Your results may vary.

Good luck.