Hi BigD,
I don't know if your daughter would raise the price for a room in Spain or not. Most hostals/hostels that I've stayed in do not have double beds, or not many, so you would probably want a room with three beds, which will cost a little more, but not enough to worry about.
I personally like staying in an inexpensive apartment myself. In 2002, I stayed in one that was very centrally located. It cost a little more that $100 a night. I would imagine the current price would now be about $120 to $130 a night.
The reason I enjoyed this accommodation is 1.) it seemed quieter and more private than a hostal in addition to really seeming like I lived in Spain again, 2.) there is a washing machine, so clean clothes is not an issue, and 3.) as good as Spanish food is, I like my wife's cooking, and when she cooks a Spanish dish, together with easily available Spanish wine and treats, let's face it, I'm in heaven.
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"I swear -by my life and my love of it -that I will never live for the sake of another man, nor ask another man to live for mine."