You can do your own sync with a cloud service such as Dropbox, Google Drive, or iCloud. It's not as seamless as the Obsidian sync, but still very good. And if using iCloud then you can have access on iPhone or iPad as well, all of this without paying Obsidian a dollar. This said, considering how critical this tool is to my work and life, and the fact that they don't try to own/use my data in any way, I have no problem with paying a relatively small amount of money every year to support the company.