Yes its free. It is a bit slow though. You'll have to try it and see if it works for you.
If all you want to do is use the command line though, look into somthing like openssh. That will let you connect securely to your box and work as if you were actualy signed on there. Its nice. Don't use telnet though, anyone can break into that. If you want a openssh client for windows, check out putty. Sorry, I don't have a link, but a quick google search should bring it right up for you.