I can do the same at my office:
Pay me $50 for the frame plus 50 for each lens or
Pay me $199.98 for the frame and 2 cents for the lenses. If they are "selling" you the lenses for 2 cents, common sense tells you they over-charged you for the frame.
It's a way to sell you the lenses by you buying the frame. Keeps you from going elsewhere to get lenses.