Whenever I read posts like this with millions of requests per small time unit, fighting over dollars. I realize I work in a completely different realm. I have barely 60 concurrent users but these users are paying top dollar for the privilege. Can't you make the revenue per request higher so this becomes a none issue ?

It will be much faster to try it out rather than waiting for internet strangers to answer for these type of questions. I would setup $10-$20 VPS and test max performance then extrapolate from there.