I've wondered if this can be built with a limited budget, in terms of cloud costs. At least it feels like you'd need a lot of hosts to satisfactorily index the web, and store the results so that you can return results instantaneously.
With limited budget and the right results, I think people would pay with “non-instant” results. Even 5-10 seconds might be perfectly fine, and that’s “easy” on a limited budget.
