AMPlify Audiobooks is hands down your best option for distribution! But it doesn’t need to be the only solution. For the widest distribution, we recommend Authors Republic as a digital distributor. Although the market share of audiobook sales and distribution is dominated by ACX (division of Amazon – surprise! not), that does NOT mean it is the best distribution option. In fact, choosing ACX limits your distribution to Audible and iTunes. They also generally pay the lowest royalties.
AMPlify Audiobooks, on the other hand, is a direst sale platform that delivers the highest royalties on any platform, and it also provides you with WAY more control (and sales info details!) than you can get anywhere else.
If you are wanting to publish audiobook only (not already as an ebook or print) or audiobook first, AMPlify is pretty much your only option.
Another retailer of audiobooks for specifically educational materials that may be right for your material: Scholastic’s Learn Out Loud.