The answer entirely depends on what the people who already hold Bitcoin are willing to sell it for. Generally, a massive buy would be expected to push the price up, because you would first buy up all the coins at the current spot price, and then the coins just above that price, and then just above that price, etc. How high it goes would just depend on the ‘depth of the orderbook’(how many bitcoins people have put up for sale at whatever prices).
If there happen to be 100,000 bitcoins up for sale at the current spot price, then perhaps you could make the buy without pushing the price up at all. That seems less likely, but it is possible. At $8250 per bitcoin, that would amount to $825,000,000 USD. So we should expect it would cost you at least this amount, unless you can find someone willing to sell at less than the market rate (they might be stupid to do so, but it is possible).