You got to spend a couple hundred bucks to get a compressor that will fill a tire in a reasonable amount of time (less than a minute on a soft car tire). Unless you are using the compressor in your garage for other things its probably not worth the money, compared to spending a buck at a gas station every few months.
On a 700 mile vacation trip home with a slow leak in a car tire I learned that all Sheetz gas stations have free air pumps. From that one sketchy road trip they have earned my business for a long time to come.
If you want to get a compressor for tires, make sure its at least 1 HP. I have a small airbrush compressor that I use for bicycle tires, and it can take 5 minutes to inflate a soft car tire.