Regular household oil is fine. If you just have one or two knives, or so, someone could take a can of 3-1 oil, squirt a little into the corner of a plastic baggie (for example), and you would have (literally) a lifetime supply of lubricating oil.
If you have , say, a couple of hundred knives, that same guy could just squirt a little more into the corner of the baggie...and you'd still have a lifetime supply.

(seriously)
Alternatively, a man without firearms could go out and buy one can or small container of super-high-tech lube, and have enough for his lifetime and the lifetime of all of his neighbors (many of which will own firearms [thank God!]).
The beauty of the high-tech lubricating oils, at least when it comes to knives (guns be different), is you can spray and squirt that stuff all over the place. You can make your knives literally *drip* with this high-tech lubricating stuff. I mean, you can lubricate your knife, your workbench (and whatever's on it), your clothes, your buds, and the floor all in one shot.
I like 3-in-1 or some other cheap, light, standard, everyday, household oil.