When you begin the game, do you start with Commodities on your race sheet? The "First Game Setup" doesn't explicitly say that you do, and I couldn't find it anywhere in the reference book either. When you do the Trade primary secondary, you "replenish" commodities, which implies that you are, well, replenishing ones that were spent, with then implies that you had some to begin with. That's a pretty weak argument for starting with them, though, when the rulebook doesn't say that you do.
Based on that, with the precedent that you don't start with any Action Cards, I'm guessing you do not start with any commodities, but I'm curious to see what others think.