Shepard Paine, one of the most respected military miniature sculptors and painters ever, says, in his book on the subject, that there's no practical difference between turpentine in a 1 oz. bottle bought at an art supply store, and turpentine bought by the gallon at a hardware store. He also says hardware store "paint thinner" does the same things. I'm perfectly content to believe him.
Art supply stores do sell other thinners for oil paints, differentiated mainly by how much they smell. I have a bottle of Winsor and Newton "Oderless." I don't have a good sense of smell, but to me it smells distinctly of turpentine - but nowhere near as strongly as the traditional stuff.