One of my solutions is free…in a way. I back up to Amazon Photos, as it is included with Amazon Prime. However, so was Prime Video until they added ads, so it is not a guarantee this will continue and I never use it to retrieve photos, just as an extra location. The most popular photo sharing and storage site is probably Google Photos right now, though there are plenty of alternatives. I have stuff there as well.
I needed a place under my control to organize and share my photos, not just a disorganized archive. It was time to migrate to a less expensive self hosted solution, backed by my NAS for storage. Then I could incorporate my existing multi location backup system to keep the files safe.
Immich
I had heard a lot about different self hosted solutions, but the most popular one I keep hearing about of late is Immich. Immich is in beta, but it is meant to reach stable this year. It already seems to be extremely stable, but it warns that you should have a backup strategy outside of it, as it is not meant to be a backup strategy by itself. I already have one, once I include this in the pipeline.
Immich is a full fledged system for photo sharing and organization. It supports showing photos on a map, face and object recognition, and more. I can easily share photos with expiring links or ones that will last forever. There is an API I can use to integrate with other systems.
While there are alternatives, such as Photoprism, Immich has a familiar design language, modern features, and offers a mobile app which can automatically backup your photos into Immich.
Please remember, if you simply upload to Immich, or any service, and purge all other copies, that isn’t a backup.