A free ebook/PDF available – DNA Buying Guide: How to Buy the Right DNA Test Kit: https://www.amazon.com/dp/B07QSBPQK3/ (not an affiliate link; offer ends April 26, 2019. You can also download the PDF version https://dnabargains.com/free-dna-buying-guide/.
This is a great ebook to read if you haven’t purchased a DNA kit. I would recommend it even if you have purchased a DNA kit.
You can also check out his Free DNA Resources: https://dnabargains.com/free-dna-resources/.