Go to kayak. My all time favorite.
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not always. last year i went to india. i looked up everywhere i couldn't find anything cheaper than 1300 from Toronto. i searched Kayak and velocity N what not. fares from tornto is always much higher than via the US coz of the taxes. these days airlines are hiding their charges under the disguise of taxes. not many people look the break up of those taxes. its normal to charge over 300 in taxes for a ticket from toronto to delhi. [they hide fuel surcharges too]...anyways, so i went directly to American Airlines and in my search i included AApartner airlines and bingo i got a cheaper fare...for less than 900 dollars plus tax toltalling 960 canadian. so, it pays to be patient and know ur options.**