According to the Playstation Blog, you will soon be able to change your PSN Online ID with an upcoming beta program. The first ID change will be free, but any additional changes will cost you $9.99/each.
This has been a long-requested feature for gamers who set up their PSN ID years ago to look something like “xxxREALN00BKLLURxxx”, and have since sought an escape from the purgatory known as “poor life choices”.
The preview for this feature will be rolling out soon, and ending late November. The feature will be rolled out in full early 2019, so keep your eyes open for it!