You can purchase books directly from me (well... mostly so) via Gumroad. When you buy a book, only a portion of your money goes to the author unless you buy directly from them. Gumroad is the closest I can get to direct sales while avoiding the hassles of rate calculation for sales tax. Gumroad will get a percentage of sales, which I consider a fair trade for them dealing with sales tax complexity.
You can also find my books on various retailer sites, including:
Don't see the book you want in your preferred store? Check my Books2Read profile.
Please note that some books are currently only available on Amazon. Amazon is the only retailer site where I regularly earn money, so making books exclusively available there has essentially no negative impact on my book earnings and enables earning from people borrowing my books in Kindle Unlimited (which happens more often than selling copies). If you want me to make more books available through a different retailer, I welcome that input - and sales of the books I already have available on your preferred platform to convince me that it's worth considering.