There is a possibility that you already know you can change your Online ID on your PlayStation for free. The featured was launched on April 10th, and it is available on Settings » Account Management » Account Information » Profile » Online ID (video below). You will be prompted to log in with your email address and password, and you will be able to change your PSN Online ID.
However, please note that changing your PSN Online ID might cause damage to your account on some games. Some of them will lose content, others will lose connections and settings, and you also might experience losing stats and progress, and it will suck. The list of the Games tested with the online ID change feature is available here, please take a look, I did not have any problems so far.
Also, you may choose from keeping a note for 30 days under your new PSN id with your former PSN id, for your friends to understand better what is going on. Here is also a video made by Sony that explains the route to the exact place in settings when you can change the PSN id. Please note that the first time you can change the Online ID for free (as coming back to the old online id also), but after that, it will cost 4.99.