We've been trying db4o for persisting objects on the compact framework. It works very well from our tests so far. However, it appears they are on the expensive side for small startups with minimal units needed. Does anyone know of any similar object databases for the compact framework? How about a open source one that is free for commercial use? :) Thank you. EDIT: We're really looking for an object database. We don't want to create our own persistence framework at this point and would prefer being able to just save/retrieve the actual object trees.