I would like to know if the egress fee for downloading is standardized. How much would it be to download lets say 10Gb onto my personal computer?
I don't have specific data on the egress fee structure as it is something set by Google and not by FireCloud itself. However, I do know that you can find out how much it would cost through FireCloud.
In the Data tab in your Workspace, you can click on any blue file link in the table that you'd like to download. It will pop up a dialog with information about how big that file is, as well as an estimated download cost. I found one in a personal workspace that was a bit over 10GB and cost $1.31 to download, to give you a frame of reference. (see screenshot below)