Getting huge traffic and investing just few bucks? If the service go down for a long time, you will loose much more, also positions in search engines. I recommend to think one more time and order a reliable service.
As others have stated, your best move would be to find a company you've done research on and use a cloud or VPS plan -- shared packages won't help you at this point. Congratulations on the traffic though. You can definitely find VPS packages this low, but with either basic server allocation specs or unmanaged/without a control panel. If you don't know your way around servers, I'd recommend increasing your budget just a bit.