How many times can i try for my US Student Visa?

You need to wait as long as possible. Don't just turn up with exactly the same info as before. Why were you denied the visa the first time? As far as I know, refusal under 214B is usually because you can't prove you intend to leave the US once your visa expires. You need to use this time in between attempts to find out how to prove that you do intend to leave after that period of time and gather the relevant doents. Ask other foreign students (who have sucessfully obtained a visa) how they did it, i.e. what doents they had to present and what questions they had to answer.