 I'm saving the cash I earn from using Upside to help pay for a vacation later this year. Download the free Upside app now to earn cash back every time you buy gas. Use promo code YEAR to get an extra 25 cents per gallon on your first tank. You can cash out anytime right to your bank, PayPal, or a gift card for Amazon and other brands. Just download the free Upside app and use promo code YEAR for a 25 cents per gallon bonus on your first tank. That's code YEAR for a 25 cents per gallon bonus.