When I want to buy a book, can I say "where to buy this book"? I just tried to search "where to buy" on google, there were a lot of search results. But I feel it doesn't look right. Do you have any ideas?
Don't confuse questions
Where do I buy this book?
With phrases that are not full sentences, such as "where to buy this book". That phrase means "the place that sells this book". You can use it as:
Please tell me where to buy this book.
The question would be better phrased as
Where can I buy this book?