I agree that both a) and b) would have a similar effect in that the widget manufacturer puts to work resources (labor, machines) which would otherwise not be utilized. I wouldn't recommend either a) or b)

Then why did you say this, in the very comment I was replying to?

Therefore, the economy would be helped if your choice increases the total amount of money changing hands,

That's the same as recommending a)!

because there are many more efficient ways to stimulate the economy

It doesn't matter that you can think of better ways; the problem is with a view of the economy that regards either of a) or b) as "good for the economy". And you in fact hold that view.