I don't know of any places that provide free air anymore. It seems that once one gas station realized that they could charge for it, all of them did.

I have a floor pump with a built-in gauge that I use at home, and a smaller one I carry around in my backpack in case of a flat.

I can count the number of times I've had a flat when I've been too far to walk to a gas station and the smaller pump has been invaluable in that, even if it is less than graceful due to it's small size.