(Note of course that in the mousetrap example it's not just your buying power that changes, but everyone's. Everyone gets the ability to buy the new mousetrap,

(Note of course that in the mousetrap example it's not just your buying power that changes, but everyone's. Everyone gets the ability to buy the new mousetrap, something of value that just didn't exist before (and the value of that new thing exceeds the value people pay for it, after all that's why they're paying for it). So despite people paying you their buying power actually increases, and so does yours. That is why the economy works. Perhaps it's easier to imagine this happening if it's a computer rather than a mousetrap)