You ought to read a ton of books, and only implement a fraction of the ideas, depending on what you have time for.

• Reading books is quite cheap. Kindle editions of popular books cost less than a nice meal. Libraries and borrowing books means you often don’t even need to pay that. Even the time spent reading a book is a fairly low investment. 
• Implementing ideas, in contrast, is often quite expensive. Implementing just one idea from a book can take more time, money, or effort than reading the book itself. Implementing all the ideas from a single book might take years.

A book you never explicitly try to implement can still add value. Perhaps not life-changing, but is has enough value to justify the relatively low cost invested in them.

Most books won’t change your life. But then again, you don’t need a life-changing amount of money and time to consume them. If you pick good books, read them well, and think deeply about their implications, that’s enough to earn back their price tag (both in terms of money and hours spent).