As mentioned, most albergues are already very inexpensive, with the municipal run very cheap. Food I found added to the overall cost at the more expensive, but you didn't have to eat there, thus reducing the price. Some albergues will charge you separate if you have the community supper, and or breakfast. As it got crowded, I began only paying for the supper...the reason is, that as I was a late riser (often the last out) the food was already taken with none left for me. Sadly, this is because many early risers would eat breakfast and then take another helping for lunch.
I had four days in Santiago before my flight home so I booked into the Pousadas de Compostela Hotel Virxe da Cerca. What a treat, the 15th century building was a former Jesuit residence and not cheap, but a pleasure...I saved money by stopping at the supermercado just up the street for vino, sausage, cheese, fruit, etc. Sometimes cheap is good...but a treat is fantastic!
Buen Camino
Arn