Hi, there is a site called atyourprice.in
Its a wonderful concept by some iit graduate. every flight travels usually with some empty seats. the funda here is, we bid for those empty seats.. usually bidding starts about a week before the actual travel date. so if there are some seats left, the airlines will evaluate your bid and then decide to accept/decline. usually you can get around 10% - 30% off on the regular fare.although never heard about 30%. I have used it for a round trip and saved about 800 bucks.
a small problem is when the bid is accepted they wont reveal the flight details and timings(after you make the payment they will give the full details of flight name and timings) they will only say in this time frame.. eg: a flight departing between 4am and 9am. but usually there is a tricky way to find out which flight it is. I go to any travel portal like yatra or makemytrip and search for flights leaving during this time frame and you can pretty much zero in on ur flight.
just give it a try and bid for a few flights and see. Let me know if you have any problems. also there is a ticker which appears after you have given a search criteria and it will show the latest bid accepted to give you a rough idea at which amount you should be bidding . i usually bid at around 700-800 below that amount and keep incrementing at 100 bucks until its accepted.
Cheers
PS: I just checked out their site and they have added a new feature showing the latest prices available online. So you wont have to go to other travel portals. Just start bidding at around 500 bucks lower than the cheapest fare available