I don't want to maintain a server, or keep my computer running 24/7. I just want to to have control over my files, and be able to sync between all my devices when I am home.
Here is how to install ownCloud on a Synology DiskStation. I have done that, and although this old NAS is a bit slow, it works.
However, the server will need to be running for you to access/sync your files - so you will need it running any time you want to look through/sync/etc. Ideally, you could get a low powered server (an old laptop, a raspberry pi, etc.) that is cheap to power and you can simply leave it running all the time.