For example at a place such as Astraweb you can buy 180 GB for $25. That would work out to 10 cents per 700 MB CD that you download.
There are many advantages of usenet. For example the encrypted connection, no one will have your IP address from a public tracker and you can max out your internet connection guaranteed.
In addition usenet is the way to go if you ask me and safer. There are tons of free trials out there. You could download over 100GB for free with the amount of free trials out there and at maximum speed that your connection can support. With usenet you don’t have to worry about seeds, sharing, or the other BS that comes with torrenting.
Therefore, among other things, I prefer usenet.