Bus timetable for Santiago (bus station and Airport) via Lugo bus station. Total cost is about €15
For most up to date timetable consult:
http://www.empresafreire.com/html/ingles/seccion3a.php
and
https://www.monbus.es/en/routes-points-of-sale/123/travel-to-sarria/
For most up to date timetable consult:
http://www.empresafreire.com/html/ingles/seccion3a.php
and
https://www.monbus.es/en/routes-points-of-sale/123/travel-to-sarria/