For Google? You think Google get a monthly bill for their bandwidth?
Whether 100TB or 1500TB of data are delivered to one ISP at one peering point in a given month has minimal effect, that 10Gbps, 100Gbps or larger port is a fixed cost that will exist regardless of traffic.
Whether 100TB or 1500TB of data are delivered to one ISP at one peering point in a given month has minimal effect, that 10Gbps, 100Gbps or larger port is a fixed cost that will exist regardless of traffic.