You can buy them at a special price on offer at Amazon from this link: http://amzn.to/2qGa5UZ
I take the old quickset locks off and put a new one on. These have a lifetime guarantee but only if you are the original owner. My old ones door knob kept falling and the inside would not turn to open the door. Lucky that i did not have to drill all the holes for the handle and deadbolt so quite a simple replacement. Register your product right away if you buy one. I did and that was even a pain to do.