Is broadly accepted to necessarily mean at no monetary cost. Its use is appropriate in advertising and marketing or speech and its use is recognized to imply no monetary Expense. I might only change the use in a scenario where by clarity and accuracy have been genuinely important, like in https://docs.google.com/document/d/e/2PACX-1vR1aRmbt0UmT4gxVq4IXbfDVfh2KrMfGfIz30gs2kLcIKk8h4EVktV5g2U8cNCzOTBSOZHhUqlkGaRY/pub