Air Inflation

Helga (the Audi wagon) has been beeping at me for several days about needing air in the tires. Don't know why but this is the second time I've had to fill the wagon wheels up. Today I stopped for gas and pulled out the pressure gauge and, sure enough, all 4 tires were running lower than recommended. Must fill them up so I can do my part to save the environment right? I pulled up to the air pump and grabbed a couple quarters only to find I needed THREE of them. Really 75 cents for a couple minutes on a compressor? I remember when it was free, which really wasn't THAT long ago, at least since Michael Jackson was actually popular for his music and not as a circus side show.