ezeego1 has three types of offers for domestic tickets:
Flat 25% cashback using SBI credit card
Flat 30% cashback using ICICI credit card
Deal of the day on domestic flights - keeps changing every day. Today's offer is 25% cash back on Indigo, two days back it was 40% off on Kingfisher, and before that it was 40% off Jet Airways
Keep an eye out on the site and book whatever suits you best.
Note that the discounts are only on the base fare - that is the convention and no one really gives discounts on taxes and surcharges. Alternatively if you are booking a return fare, I strongly suggest you to have a look at the Jet Konnect and Spice Jet sites. They have extremely good return fares.
yatra.com also has this special 50% off on bookings made using a Citibank Debit Card on Wednesdays