How do you say free in japanese?
As in the context:
This book is free.
What's the word for 'free' here?
Apart from 無料（むりょう）、ただ(タダ),
One more common word that mean free - サービス (coming from English word service. Seems that Japanese people consider service as free stuff!)
- この本はサービスです (This book is free)
Also when you buy stuff and there is a complimentary item, it is called おまけ（御負け）
- この本はおまけです (This book is complimentary)
You can of course use the imported word フリー
- この本はフリーです (This book is free)