My sister recently got really into soapmaking, since we have enough surplus goat's milk to experiment with now. She's made 4 different soaps so far, some of which are great and some of which need a little more work.
She likes Brambleberry, Wholesale Supply Plus, and Nurture Soap for additives (fragrances, colorants, etc.). As far as ingredients like different oils and butters she found Amazon, Etsy, and the local grocery store to be cheaper than the specialty companies. As far as additional resources, she is a member of Soapmaking Forum (that is its actual name
), and she loves the YouTube channels Royalty Soaps and Elly's Everyday Soapmaking, both have great tutorials and free recipes that are well-tested.
I took a look at Beehive Alchemy, since I had never heard of it, and that looks like a great book! I'm seriously considering buying it.