You can buy gift cards from retailers at a discount from online resellers and then purchase discounted Uber gift cards at that retailer. Some examples are Winn-Dixie or Kroger, which sell other company's gift cards at a discount, sometimes significantly. In addition, there are trusted Uber gift card resellers on eBay that have sold them for as much as 15% off. Also, Amazon, Target, etc sometimes offer 20% off Uber cards.

When I get over a 20% discount, I back up the truck and buy $500 to $1,000 at a time because I know my friends will take some off my hands.