https://www.theverge.com/good-deals/2018/7/24/17607380/avis-amazon-gift-cards-rental-car-deal

Avis will begin offering free Amazon gift cards to Amazon customers who rent cars from Avis. Through the new offer, Amazon customers will be eligible to get gift cards for 10 percent of their rental cost.

Starting later this month, customers who book a rental through the Avis Alexa skill will get a gift card for 20 percent of their rental’s cost, which could be a pretty nice chunk of change, assuming you’re willing to navigate through the voice menus.