How do I change the locks on multiple doors but use same key?

To try and save money on a locksmith, I%26#039;d like to change the locks on my house doors myself. I have installed locks on single doors before but how or where do I get locks that use a single key? Do I buy a set or is that something I need a locksmith for? Thanks!!|||Most hardware stores (even Walmart) can help you. Basically, you pick the style handle you like. The handles use different keys at first. The clerk at the store uses the key from one of the locks to %26#039;key%26#039; the other locks to use the same key.|||Nope, your home improvement store sells this very thing--multiple knob locks and/or deadbolts keyed alike. Just walk in and ask.