Starrett makes great tools, I wouldn't compromise on the oil to lubricate them. It's about $6 for 4 oz, but you typically don't have to use much or very often. If that IS the case, maybe you can buy it in a bigger quantity and just refill the small bottle.
I also have a nice number of Starrett tools including a 0.0001" dial indicator. I keep moth balls in my tool box. Old time method to keep a very fine oil atmosphere in the box. My Starrett tolls are 50 years old and look very nice without any rust or surface blemishes.