I don't skimp on oils and cleaning products, no matter whether it's for use on guns, tools or machinery. I feel the cost of a tried and true proven product is not worth chancing a bulk substitute that may or may not work as intended. I like Ballistol so I buy it, a little goes a long way. I use a lot of Marvel Mystery Oil which is not very expensive, about $8 for a quart. I use the Marvel Mystery Oil for light lubrication of moving machine parts as well as for drilling or cutting tools. It is primarily a light mineral oil with added solvents, probably about 5W viscosity.
I know folks who will buy an expensive $700 to $1,000 plus Stihl chain saw, which is one of the best brands in my book, and then buy the cheapest SAE 30 weight oil for their gas mix because they want to save money. They then wonder why after a few weeks of using the saw they have burned the engine up or damaged the rings and piston at a minimum. Sure SAE 30 oil will mix with gasoline and provide lubrication and limited protection, but will separate and eventually settle to the bottom of the container; therefore, if you don't shake the container each time you use it, one might as well just use straight gasoline.