I have one, but I have pretty much stopped using it, the most I have ever seen as savings is 1.5% which works out to about $.45 a tank. The reasons I stopped using it is that you start to stop paying attention with how much gas you are using, and you end up spending more somehow on gas than you should be. The other and much bigger issue is that they constantly have billing issues, sometimes the charges do not show up for 2 weeks, sometimes they show up that day, and other times you will get hit for 3 or 4 charges late Sunday taking all the money you just made over the weekend. Which would be fine if they were all actually your charges, but I have caught a couple of errors, and of course Uber still insists they are not errors and are my charges.