I use a Ryobi 18V inflator. It's slow, and the gauge is totally inaccurate, but its inexpensive and it is great for making adjustments to tire pressure. If you need to air up a flat it is going to take a minute, but it will do the job.

Mine is a few years old, they have some different ones now that may be faster and better. Mine has an analog gauge and I see some newer ones have a digital that might read correctly.