The vast majority of what we would call "super highways" have no tolls in Spain. This map, from 2011 may not be totally up to date but should give you an idea of where the toll roads are (and if you can figure out the rationale behind the decision of which roads to put tolls on, you get the gold star).
https://www.autobild.es/practicos/autopistas-peaje-espana-165309
I believe, but am not certain, that the tolls vary depending on time of day -- the higher the average traffic at a certain hour, the higher the toll.
I looks to me like you may hit an occasional toll (for example, leaving Madrid heading north, going from León back east towards Pamplona), but I don't think tolls will be a major price factor in your calculations.
I have been in Hospital de Orbigo during their Renaissance Fair. We had no idea we would be happening upon it, but luckily there were rooms in an albergue. Lots of merriment, that's for sure! Buen camino, Laurie