6 For free is an informal phrase used to mean "without cost or payment." These professionals were giving their time for free. The phrase is correct; you should not use it where you are supposed to only use a formal sentence, but that doesn't make a phrase not correct. I want to make a official call and ask the other person whether he is free or not at that particular time.

Understanding the Context

I think asking, β€œAre you free now?” does't sound formal. So, are there any alternatives to...