Ds220j or Ds223

[ed]

The J series NAS only has 512MB of memory. This is OK for file storage and backups. But if you want to explore what NAS can do you need at least 1GB memory https://www.synology.com/en-uk/products/...220j/DS223

Also if you do not want any limits on apps you can install then DS220+ is the best option.