There is no cost to use the Wunder app.
There is a ₹10 / ₱10 transaction fee on Wallet paid rides. However when you take a Wallet paid ride, Wunder rewards you with different weekly or monthly campaigns. Find the current campaigns on https://wunder.org/blog But please note that any cashback or rewards from these promotions is transferred up to 48 hours after the ride is paid, depending on holidays. There is no transaction fee on cash rides but also no cashback opportunities!