How much does such an option cost? I couldn't find pricing in any article, but I suspect that airlines that paid extra for the disagree light will be looking f

How much does such an option cost? I couldn't find pricing in any article, but I suspect that airlines that paid extra for the disagree light will be looking for a refund now that Boeing is offering it for free. I wonder if it's like buying a car where in order to get that one option that you want, you need to buy a whole expensive package of other options that you don't really want.