said by Jerm:
At overage rates $10GBx300 = $3000!
If you want to pay $3000 a month, you can pay for a dedicated line. The costs to run the line will either be paid by you up-front, or amortized over a contract period. Nobody will care if you push multiple terabytes through in each month, as you have paid the full costs of the line and are not impacting other customers.