Can i get toricredits just by play the game, or i need to buy ?

you can do both . tc ingame is few . maybe you want to buy some right? here it is
http://forum.toribash.com/tori_depositcredits.php
http://forum.toribash.com/tori_boosters.php

You earn 10 tc per match when you play in official servers. Here's a picture of what the official servers look like


You can play in-game tournaments as well. There are 500 TC tournaments and 750 TC tournaments, meaning that you'll earn that much if you defeat all other opponents.

You can also look into betting and dueling, but I wouldn't suggest that until you've got a decent amount of experience.