DVR Hard Drives

I got my mom a DVR for Mother's Day, but it doesn't have a tuner so she can't record shows on different channels without coming home in between to change the station on the cable box. I can't find a DVR with a tuner, so my next thought was to get her a DVR with hard drive but those are hella expensive. The only other choice I see at the moment is to pay for the Comcast DVR or get Tivo. I don't know which of those would be a better chouce but I was hoping in the beginning to avoid another monthly bill to pay.

So my real question is, does anyone know of a DVR with Hard Drive that won't require me to cash in my 401k already?