Sewing machine oil is a pure, acid free mineral oil, around SAE10, so quite light. The bottles I have had over the years have varied a bit in thickness, not much, and it has never been a problem.
It's the same oil used for bicycle chains, but be carefull when buyting these days. Most oils are something else than the basic oil, optimised for particular conditions, with additives that might make a mess in a sewing machine. Motor oils are too heavy to be ideal, and the various additives can be less than an advantage in a sewing machine.
I have never needed lubricants in large quantities, 120 ml last a year at least and I use it for more than sewing machines.
If you want to venture into different oils, Finish Line Ceramic Wet Lube, and TriFlow are the only ones that have tured out well in the long run. There's too many brands out there to have a comprehensive view of the situation and the additives varies a lot.