The Beloved Eagle 66 Squirt Oiler (2019) [video]

I use a catsup bottle...I do have a bunch of antique oilers, but most of them are top heavy and fall over all the time and leak out

Machining is curious in that it's both expensive and not. The mill/lathe will cost a good chunk of cash, but if you have good enough tools to start with you can make a lot of the other tooling cheaply, and it's very much a common thing to do it as a personal project.

Cash saves time and provides conveniences. You don't even need an oil can for some things, you can use any random tin or the bottle the oil came in. Or you can make your own.

Buying a $125 oil can is just an eccentric oddity for the most part. There's plenty of cheap ones for sale at Amazon. Many of those are flawed, but they'll still work as an oil can.