One "trick" to know is that transit links are generally billed as the higher of inbound or outbound traffic. If you have a service which is unbalanced and push

One "trick" to know is that transit links are generally billed as the higher of inbound or outbound traffic. If you have a service which is unbalanced and pushing out a lot of data (like most hosting services), your inbound is thus essentially "free" up to a very high volume.