If you want to use spanner but don't have a large data workload I would recommend looking into firestore as it is built on top of spanner.
http://firebase.googleblog.com/2017/10/cloud-firestore-for-r...
http://firebase.googleblog.com/2017/10/cloud-firestore-for-r...
Firestore also differs a lot from Cloud Spanner, most notably in the way that it can be used directly on the client, whereas Cloud Spanner is meant to be used in combination with a server side application.
"And for you database aficionados out there, we should point out that our multi-region database offers strong consistency (just like Cloud Spanner!),"
https://cloud.google.com/datastore/docs/concepts/structuring...