DVR for Time Warner Cables

Hey guys,

I cancelled my dish service about a month ago, and I it hasn't made much of a difference in my life. I have Netflix, Hulu Plus, and Amazon Prime. I'm considering getting Time Warner because we want to watch sports. When looking at prices i noticed that they charge like 20 dollars to "rent" a DVR, I would rather buy one. Any suggestions on what I can use with a cable card?

Thanks.