Choosing an air compressor will depend on several factors including how large your operation is and how much you are willing to spend.
The type of air compressor you need depends on your workload. If you have a high workload, you need a high capacity compressor. If working on cars is a hobby, all you need is small five gallon compressor.
Air compressors can cost anywhere from $100 to $5,000 depending on several factors.
If you own an automotive repair facility, an air compressor is essential and you should purchase a compressor of high quality, high capacity and fast fill time.
There are many great manufacturers of high quality compressors; Ingersoll Rand is one of them. There are many other companies that manufacture air compressors and you should compare them to see what fits your needs and budget.
Air compressors accumulate water inside of them and need to be drained everyday. If you don't do this, the tank will rust internally and fail (rupture) down the road.