Silvercar, an airport car rental service that allows you to book an Audi A4 with your smartphone, is offering a $100 referral bonus when you refer a friend who rents a car for two or more days before Dec. 31, 2014. In addition, when you refer five friends who rent a car for two or more days before Dec. 31, 2014, Silvercar will give you an additional $500 bonus. Silvercar is unique in that customers can locate and unlock their rental car using the Silvercar app rather than heading to the rental counter and waiting in line. Silvercar is currently available at Austin, Dallas Love Field, Dallas Ft. Worth, Denver, Los Angeles, Miami, Phoenix and San Francisco airports. Visit http://www.insideflyer.com/link/?11850 to learn more.