Skype Usage
In skype:
Tools--> Options--> Advanced--> Connection-->
Then tick "Display technical call info during calls" and "Display Skype bandwidth usage"
Now while in a call you can hover your mouse over the call window and it displays a massive popup with all the bandwidth details!
configure Skype not to run at startup and thus to only have it running when you need it. There's a little check box in the Skype configuration which does this. By default Skype as installed will run at system startup.
A quote i found elswhere but seems no one has the full answer except skype and they dont give the true figures out (no suprise there lol)
if im using only chat, about 30-60kbps
if im using a voice chat, about 80-130kbps
if im using a video call voice chat and a chat, 200-500kbps
it really depends on the connection especially the camera feed