Pee , if you can afford to go on holiday for 25 days im sure the the price of the flight is not a worry.
Many people from Scandinavia have second homes in Spain, so the duration of their stay could be irrelevant. But anyway, I don't want to cast doubt on prices here, I'm almost happy for FR they can afford to dictate that kind of fares. The only issue is the following one: Why Ryanair prefer to sell 2-3 short flights for 3-9 €/£ each very often indeed and on many routes when the same plane could have been used for 1 longer route (like the mentioned one) with the price tag between 100 and 200 €/£ continuously. Pure economy, nothing else.