yes I want to know if trial class is free ?

It's possible to take "trial sessions", which are 30 minutes long and usually at a discounted price. The teachers' profiles are full of information and student feedback, plus some of the teachers also have a presentation video, so just looking at a teacher's profile will tell you if he/she is a good teacher and if he/she is suitable for you. If you fill out your profile fully and help others on the site, it's more likely that people will help you in return. You can also look for language partners for an exchange. http://www.italki.com/partners (This part is free.) :)

Please give us some context. Do you want to know if the first class you have with any Italki tutor or teacher is free?