Google mixes AuthorScale pricing with AuthorShelf because the names sit next to each other. They are not the same company or the same product.
AuthorScale pricing (marketing software)
AuthorScale is a content/scheduling app for authors (TikTok, Instagram, YouTube). Their public pricing page (verify live) has shown Starter about $19.99/month, Pro about $29.99/month, Ultimate about $49.99/month, and a lifetime option around $999.99. That is software, not book production.
AuthorShelf (self publishing packages + author services)
AuthorShelf Inc. (Maryville, TN) sells listed self publishing packages from $399–$2,989 and à la carte author services such as book cover design and formatting. Lifetime portal. No monthly portal fee. You keep 100% rights and net royalties.
Do you need both?
If your book is not produced yet, a social app will not replace a cover, interior, or ISBN. If your book is already live and you need posting volume, a marketing app can sit beside AuthorShelf after Title Live. Side-by-side: AuthorScale vs AuthorShelf.