"For free' is grammatically correct. It is an idiom of the English language.
Yes, 'for free', is grammatically correct.
"Not like that" can be grammatically correct, depending on the context.
Yes! That is grammatically correct!
The phrase "Is you don't miss me do you" is not grammatically correct. It should be rephrased to something like "Don't you miss me?" to be correct.
All are acceptable (for free, for nothing, gratis, free) altough for free does not seem grammatically correct.
The phrase "You are not knowing" is not grammatically correct. Instead, you can use "You do not know" or "You are not aware."
Yes, it is grammatically correct.
Yes, Almighty God is grammatically correct.
"That was wrong" is a grammatically correct sentence.
The sentence "Rhoda's Crazy" is not grammatically correct. It is missing a verb to make a complete sentence.
'What a drunkard you are' is a grammatically correct English sentence.
The sentence is grammatically correct.