I really loved the La Napoleon Auberge just outside of town, within easy walking distance (on the Camino, actually!) Probably impossible to book, though. The owner is a wonderful Basque man, and he has an English wife. You can find out about the place only through the pilgrim office. Ask for the Auberge La Napoleon.
He (I think his name is Peli?) waits at the pilgrim office to pick up pilgrims who have just arrived on the train and haven't booked a spot, or he will come get you if they call him and he has room. He transports pilgrims in a farm truck ...there are wooden benches to sit on. The auberge is a small lovely farm with a green talking parrot in the main house, it sleeps around 12, and there's a great breakfast around a big table overlooking the road where the pilgrims are just starting off!
It was 15E with breakfast when I was there in 2013.