I live in Madrid and have parked at various parking lots near the airport several times, they really are different. The first time, in May of last year, I left my car at P1 and this parking lot is the closest to the terminal. Pretty convenient, but the total for the week was very expensive. The next time, I tried Larga Estancia. I read on https://madrid-mad-international-airport.com/ that it starts at €12 per day. It’s farther than P1, but there’s a shuttle that runs there about every 10 minutes. The difference in convenience is minimal, but the price difference over a week is significant.
