A little known benefit of a credit card you may already own is free rental car status through MasterCard World Elite. For example, my Barclaycard Arrival + MasterCard is World Elite. If you have a MasterCard (and most people d0), check the front or the back of the card for the “World Elite” title under the logo. Common airline credit cards that are World Elite include Hawaiian, American, and Virgin.
Once you have identified you MasterCard Elite, the easiest way to enroll is to call 1-855-802-1387 from the US. Currently the offers are for Avis, National, and Sixt. So what do you get with the rental car status? Here is a handy chart that shows you the benefits: