@Tim P What is your locale, sir?
That is perfectly acceptable.
Are you asking me? It may be perfectly acceptable to you but it's not to me and though it's a colloquial Americanism it's still a Pet Peeve for me. It makes me cringe when I hear or read it. In the example, 'for' means 'in exchange for' and since free is not a noun, pronoun or noun phrase one can not use it as a commodity.
Strange how most people know to drop the word 'for' when they tack on 'of charge'. ("I got it free of charge")