HELP! i need the absolute cheapest site/method for airfare?

i need to fly to ft. lauderdale (from ontario california) on april 7th. all my normal sites and ways of getting tickets seem to have jacked up their prices (too close to spring break i guess?)! we don't want to pay more than 300 a ticket and the cheapest i can find is 427! we would be spending most of our honeymoon money on airfare alone! anyone know any little known great site? should i try a travel agent? help, i need to buy tickets tonight!