PS4Me need your help, I have question about PS4

I will soon buy PS4 Slim, and would like to know whether to buy accounts? if the ban has received? if not, what should be done so as not to catch the ban.

If you're using the accounts from the marketplace as long as you don't log into the account more than once you should be good. Logging in more than once raises awareness to the primary owner of the account and they can report it as hacked thus stopping you from being able to play the game, use dlc, etc. and even a console ban, just be safe about it :P