Which sentence is correct?
If I am free,I will go with you.
If I were free,I would go with you.

Question

Answer

Both are correct but mean something different.  
First means maybe I’ll be free but I don’t know.  If so, I’ll go with you.
Second means I’m not free,but if I were I would go.

Answer

Both statements are grammatically correct but they apply to different situations.

Read Phil's excellent article.

Answer

Both are correct.

Answer

You can find a short summary of all you need to know in my brief mini-article:

Grammar boost: Conditionals cheat sheet PART 1

https://www.italki.com/discussion/164505

Answer

The second sentence:
"If I were free, I would go with you".
The first one would be correct without "if":
"I am free, I will go with you."