About Tire Air Pressure #02

I forgot to post yesterday! What's in your car's tires, everyone? It's usually air, right? For some reason, even though my car has eco tires... it has nitrogen Σ(・∀・；) The advantage is that it leaks less than air, but the disadvantage is that you can't easily refill it. They charge 500 yen per tire! So, I received a notification for an inspection, and I'll get it sorted out then lol I don't even know if it's free or paid...