The site looks great!...

But, just by looking at the homepage, It could be difficult for a NEW user to understand what's actually going on, especially pertaining to the description where you say "decide the price"

POST YOUR QUESTION

1. Type your question 2. Decide the price* 3. Choose the best answer

I'd also suggest that the tutors themselves be verified some way or the other, because anyone can claim to be an expert.

I really do like this, because you are trying to please TWO user groups; Users (students/'askers') and Tutors. That can always be a challenge.