I just ordered a bunch of these myself, I like just the cable myself so I can feed it through the old housing and not have to tie it all down again. Here's where I got mine, nice and cheap. Most have a end on the other side, but I found if you cut the cable as close to the end as you can it doesn't frey. I dip the cut end in hot wax before I feed it through the housing, just to make sure there's nothing jagged to catch inside the housing..
Brake Cable | BikepartsUSA
I would recommend sticking with the MTB cables they are a bit thicker.