You have written a good book. You want people to buy it. I have one question: how are people going to discover your good book?
Many best-selling authors claim you don’t need social media to help you sell books. People with gigantic email lists and a backlist of dozens of books say all you need is a good email list and a couple perma-free books. If your book is good, it will sell. That would be absolutely true if the market wasn’t flooded with authors who have also written good books. If you’re serious about selling more books, you need to take advantage of established channels that will get your book in front of more potential readers.