Malware Removal

So long story short I have malware attached to my mac that I can't get rid of, I'm sure i was an idiot and downloaded something I shouldn't have. I traced it down and found an article talking about it(Here's the link to the article http://malwaretips.com/blogs/valuedealshopper-com-removal/), but I have no idea how to remove it on a macbook. A friend recommended buying MacKeeper but after researching it I've seen some posts making me not want to do that. Can anyone recommend a free Malware removal app?