Unless you are anti-booking, I think it's a good idea. I stayed in three albergues (pre-booked), and two of them were full when I arrived (Bom Caminha in Caminha, and Estrelo do Mar in Baiona; the one that wasn't full was La Cala Inn in Oia).
These were my stages and accommodation:
Day 1: Porto - Vila Chã (26km) - Café Sandra (private room, €30)
Day 2: Vila Chã - Esposende (31.5km) - Eskama hostel (private room, €40)
Day 3: Esposende - VdC (25.1km) - Alex Point (private room, €42)
Day 4: VdC to Caminha (26.8km) - Bom Caminha albergue (private room, €45)
Day 5: Caminha to Oia (16.4km) - LaCala Inn (albergue dormitory, €20)
Day 6: Oia to Baiona (17.9km) - Estelo do Mar (albergue domitory, €16)
Day 7: Baiona to Vigo (25.3km) littoral - Pension Buenos Aires (private room, €45)