Here's a topic likely argued about in writer's circles, with writers, editors, and publishers all having their own opinion of the subject. As an author, especially a new one, you want to get your stories out there, but you don't want to starve while you're doing it! So where's the balance here?
Free promos and giveaways can have their place, even for an independently-published author. Giveaways can be something as simple as donating a couple of copies to your local library or hospital. You can give books as prizes for contests you may run. Or you could trade with another author at a fair or meeting in exchange for doing reviews on one another's work.
But giving your work away to the general public can be beneficial too. Kindle Direct Publishing has a program called Kindle Select, in which a book is enrolled for 90 days and must not be available in digital format during its enrollment period. They also offer two special promotions for books enrolled in the program. One of these is the Kindle Free Promo. The author can run a free promo once during the book's enrollment period as long as it hasn't been entered into the other program (the Kindle Countdown) during that same period. Books can be run free for up to 5 days, and it doesn't have to be all in a row.
Getting your book out there in this way may seem to be a waste. After all, how much might you have made if those were all paid sales? But this is a good tool for an author to utilize, especially if you have more than one book out or are nearly ready to release a second one. People get the chance to read your earlier work for free, and if you've hooked them with the first one, they may return to read other books you've written. Also, word of mouth can come into play, and they may tell a friend about the wonderful book they've just read. Maybe it's not even free any more, but they were told it's worth getting, and so are willing to shell out a few bucks for it.
If you have more than one book out, you may make a sale of another book during your marketing for the free one. This actually happened to me. The lady didn't really want my free book, but while she was there she looked at my other listed books and made a purchase.
Book giveaways can be an excellent marketing tool to help get the word out to a wide range of readers. It may feel counterproductivd, but if you can get a couple reviews out of it, maybe a few more purchases down the road, it will have served its purpose. I intend to donate some copies to the cancer center in St. Louis where I stayed for so long. Not only because I understand what it's like to be a patient in a long-term care unit, but because I'd like to inspire other patients going through a horrible experience. And even that might get me more sales later on, once the patient is well enough to return home.