The prices are low because of the off season. Yes, the SFO to Madrid flight by March is 450, but that does not include the 70$ in taxes. By summer, with many American college students going to Europe, the airlines can charge much more. If your set on going for the summer, not worry about the price, just get your ticket early. Last year, it was outrageous just to get a flight into Europe. Let alone, trying to find some great deal. Good luck. I will be in Spain in a couple of weeks. SFO to Madrid 520$ w/taxes Delta airlines. I believe the offer ended Jan 23. Take care....