Question: how many times can you change your gamertag on ps4?
Answer: Change your online ID as many times as you want. The change is free the first time. After that, the cost is $9.99 USD/CAD per change ($4.99 USD/CAD with PlayStation Plus subscription). Display your old online ID next to your new one on your profile on PS4 system and on web for 30 days, visible only to your Friends.