Storage usage is calculated in binary gigabytes (GB), 1GB is 230 bytes. This unit of measurement is also known as a Gibibyte (GiB), defined by the IEC (International Electrotechnical Commission). Similarly, 1TB is 240 bytes or 1024 GBs.
The pricing shown is based on data transferred "in" and "out" of EmbedSpace (over the public Internet). "Ingress" transfer implies data transfer from the internet to EmbedSpace, "Egress" transfer implies data transfer from EmbedSpace to the internet. If you access data through EmbedSpace or its affiliate apps, EmbedSpace does not charge you for bandwidth.