The easiest answer is CDN but I'd like to ask. A friend of mine has a server that is used for mirror downloads. He says he is doing about 10TB of bandwidth a month which shocked me (I wonder if he is lying).

I seen his site and he has no ads. I suspect he might close his website once he gets the bill. Anyways I was wondering since his CPU/RAM is not being used and his HD usage is around 15gb what he can do to lower cost if he continues this site. I said put up ads but I don't know if ads would cover it I found one CDN which offers $0.070 / GB. 10240gb (10TB) * .07 = $717 a month. That seems a little steep but he is using lots of traffic due to it being a mirror site.

Also using a CDN doesnt make sense as he doesn't need multiple servers hosting the files in different areas (which is one reason he isn't using that now). He just needs a big upload pipe

Is there something he can do? At the moment he is paying $200 a month on a dedicated server and he is using WAY more bandwidth then he should be using.

Side question: Can gz-ing files large already compressed files help? like on (zip, rars, etc)