Sure, but it isn’t recommended. There are many publishing services out there that are just software overlays for IngramSpark and Amazon. We have found many that dazzle with low rates like “10% of royalties” only to discover that this percentage is on top of normal IngramSpark pricing. Amazon is the main online retailer in the world and Ingram is the main book distributor in the world. An alternative service is usually just a pass-through for using these two publishers.